Author's WARNING: This is like, all lemon. At least 4,000 words-worth. So do with that info what you will, and it ain't my fault if someone looks over your shoulder while you're sitting on your iPhone in maths reading porn xD

' So.. H-how are we gonna do this?' Fionna asked after a moment, when it appeared that Marshall was too surprised by her immediate decision to say anything. He blinked at her then swallowed, one hand travelling up towards his head, and seeming to divert to the back of his neck at the last second.
' I, uh... To be entirely honest Bunny, I hadn't thought you would say yes so easily. I mean, you've never done anything like this before, and what I'm asking you... It's a long time for a human.'
' Shut it, I've made up my mind, don't try and change it.' Fionna told him with a hint of steel, folding her arms again.
' And also, give me a little credit, you and Femme are as bad as each other. I'm not some pure, blushing maiden, I know what happens.' Marshall-lee raised an eyebrow at her cynically.
' Not for long though.' Fionna blushed and stood up rather quickly, tucking a curl of her hair back into her hat.
' W-who told you that?'
' Who do ya think? Femme's my friend too. Well, "friend." Marshall said, raising his hands and etching quotation marks into the air around him.

Fionna sighed and looked down at the ground between her feet, then glared back up at Marshall. She was annoyed at herself for being so awkward and unconfident and freaking innocent, she didn't want to appear that way in front of him. But there was nothing she could do about it either, because she was very inexperienced.
' You still haven't answered my question.' Marshall ran his fingers through his hair before he could stop himself and then thrust his hands deep into his pockets, unable to met her eyes as he shrugged.
' That's 'cause I-I don't know. This is hardly the way and the reason most people have their first times.'
' Well, you're the one who's done it before, tell me what to do!'
' I thought you said you know?'
' Well, y-yeah but- Marshall!' She pleaded, her cheeks burning bright red and almost wanting to cry with frustration and humilation. Marshall sighed, studying her as he bit his lip guiltily. That was such a pretty colour adorning her cheeks. He had always liked making her blush, but in this case it was a mixed reaction. She looked upset, and he guessed it was the imprinting that was making him so goddamn empathetic but he hated it, he hated that she felt that way and that it was his fault.

Impulsively, he floated over to her and cupped her face in both hands, feeling his lukewarm skin heat up with the blood burning under hers. However, it wasn't just that, it was like at every point where they touched his nerves started to crackle and sparkle, sending jolts of electricity up his arm. It was like his limbs were suddenly coming alive again and he hadn't even noticed they had been dead for a week.
Fionna's breathing had sped up, and he could hear her heart thumping dramatically in her chest as he leaned in towards her. He hesitated just before contact, and breathed in her scent, and the sense of relief as well as excitement it gave him was like the first time he had ever tasted blood, the first mouthful. It was heady and intoxicating and it gave him the feeling that when he had taken all she could give he would experience true satisfaction.

Fionna felt Marshall shudder slightly when his lips first pressed against hers. They were oddly cool and it felt unnatural in a different way to how Flame Prince did. But she had little time to consider that as Marshall's fingertips edged under her hat and gripped into her hair, tugging her head upwards. When she opened her mouth and inhaled sharply at the pain he immediately made use of the gap and slid his tongue between her lips, using his own jaw to force her to open hers wider. It was unprecedented and Fionna was confused and scared for a few seconds, and she automatically raised her hands to push him off. But Marshall was holding her head too firmly for her to move, so she tentatively tried to respond to his actions. However, this only made him even more frantic, and she yelped and shoved his chest when he dragged his teeth roughly over her lower lip.
Fionna overbalanced and fell hard onto the floor, one hand going to her mouth and checking whether he had drawn blood. She could feel she was shaking, and her breathing was shallow and erratic.
Marshall-lee watched her uncomfortably, feeling a hideous sense of regret and annoyance at his own lack of self-control well up in his stomach like vomit. When she finally looked up at him, she looked frightened. Then as she wiped her mouth, she took a deep breath and swallowed, squeezing her eyes shut for a second.

' I-I know you're not... I get that 'cause it's instinctual- and also, 'cause you waited so long before you came back... I know you're not trying to be rough, you're just-... C-can you try and be more gentle?' She ended weakly, her eyebrows pulled together and blinking rapidly. That was a hell of a first kiss. She didn't regret her decision to help, hell no, but she was a little apprehensive about what might follow after that. She didn't want to come out of this as bruised and sore as she was when she fought a chimera or climbed down a skinny crevice into a cave.
' I'm sorry. I didn't mean- it's... It's hard to control.' He replied sheepishly, offering her his hand. Fionna looked at it for a second, then took it, twisting her mouth to the side. She studied him as she dusted off her backside, then bit her lip. Which was a bad idea, as the recently tenderised flesh ached in protest.
' This isn't going to be easy at first, is it?' She half-stated, frowning at him worriedly. Marshall-lee sighed, scratching the back of his head.
' No. No it's not.' Fionna poked her tongue into her cheek thoughtfully as she decided what she would do next.

Marshall opened his mouth and Fionna held up a hand, recognising what he was about to do.
' Stop. Apologising. It's not your fault.' She put her hands on either side of his face and kissed him once, very very gently, just the barest brush of skin. The fact that Marshall managed to keep himself from trying to deepen it gave her the necessary assurance she was looking for. She could do this, she just needed to make him communicate and listen to her so he wouldn't go too far.
' Wha- where are you going?' Marshall-lee questioned when she let him go and turned away, and he couldn't help be hypnotised by the pendulum that was her hips. He was disgusted with himself even as he thought it, you horny undead chauvinistic pig, because it was his gobdamn sex drive that was currently causing all his problems. But he also knew that even if he wasn't imprinted on her, with the way she acted and the way she looked now (that outfit was straight out of a fucking wet dream) he would've admired it all the same.
' Up to your room.' She answered, starting to scale the ladder. Marshall waited until she was out of sight, then took a deep breath, did not run his fingers through his fucking hair, and followed her.

Marshall balked and clenched his fist so hard that his nails dug into his palms when he saw Fionna standing at the foot of his bed, taking off the denim jacket she was wearing and her rabbit hat. There was a forced nonchalance to the way she tugged off the hat and shook her hair out, and for a moment the vampire was mesmerised by the river of blonde curls that dropped down to the floor. But he could see she really wasn't as calm as she wished she was, and after swallowing down his discomfort at how feral he felt as his eyes traced the lines of her body, he drifted over to her.
He wrapped his fingers around her wrist when she reached down for the garter strap and she froze, looking at him in confusion. There was a light shade of pink dusting her nose and cheeks, and it reminded him of a cupcake with chocolate sprinkles as he detected the freckles that resided there also. That was a detail his mind had failed to conjure up.

' Let me. I think it'll help.' He said, leaving it unspoken that it wouldn't just be helping him. He didn't want her to be frightened by him and what he needed from her. He'd screwed up, loosing it so quickly before. However, the concentration required to undress her might help him tamp down on the violent, animalistic edge to the desire, and if he could show her that he could be gentle, like she wanted(and needed) him to be, then maybe she'd stop being so tense. Her being tense was making him tense and it was not good considering how badly he just wanted to rip away the fabric that denied him access and claim her.
Steady on, man. You can manage. Don't hurt her.

Fionna gave her consent after half a surprised second, and Marshall decided he'd rather start up top then go straight for the business area. He pulled her around so that she was facing him, and he felt a flash of heat bloom through her skin as he untied the bow that finished the lacing on her bustier. He had been watching his hands, and what was just in front of them as he completed the action, but his eyes flickered up to her face afterwards and he couldn't help but smile at her expression. She looked so gorgeously naive and innocent, as well as a mixture of curiosity and embarassment. The embarrassment became greater when she saw him looking at her, and she awkwardly turned her head to the side and tucked her hair behind her ear as he started to unlace her top.
Marshall bit the insides of his cheeks to hide the intensity of his reaction when he took the leather away and revealed the cherry red and black bra underneath. Gob. He wanted to drink that colour then immediately get rid of the undeniable sexy but still barring obstacle.
Fionna's arms twitched and she clenched and unclenched her fingers nervously. She wanted to fold her arms, she hadn't be prepared for just how much looking and observing and staring was going to happen.
Marshall somehow noticed that she wasn't happy with his visual appreciation, so he eventually managed to tear his eyes away from her cleavage and instead leaned in and kissed her sweetly, carefully controlling it. Even without having made use of his tongue, Fionna was still breathless by the time he'd finished, and with a soft push on her shoulders she sat down on the edge of his bed. Marshall-lee knelt in front of her with his knees on either side of her hips and kissed her again, keeping his hands chastely placed on her waist even as his fingers itched to undo her bra. His whole body felt jittery and wild, like there was a huge pulsating ball of energy filling up his torso and just pleading and begging desperately to be allowed to run free.

He waited until Fionna tentatively ran her tongue along his upper lip before he moved his hands and returned the gesture, but she still jumped when he started to unhook the strap.
She felt guilty when he immediately stopped, and studied her, his eyes guarded and behind that, worried. He was as scared of hurting her as she was of being hurt, and he was trying so hard not to but it was still her first time, so that was enough to make anyone nervous. Coupled with the fact that she knew he freaking needed this and how harshly he had kissed her before, it was stressing her out.
' I'm sorry. I'm sorry, I just-'
' Fionna, do you trust me?' He asked, and she was about to say yes but then she thought about it. In this sort of situation, it seemed like honesty was definitely the best policy.
' I don't know.' She replied truthfully, and Marshall pressed his lips together for a second. Yeah, he probably deserved that.
' Do you think you could?'
'...Yes.'

Satisfied with this answer, Marshall ducked his head and pressed his lips into the underside of her jaw, before kissing his way up to and ever so softly biting her earlobe. Fionna discovered she actually quite liked the sensation, and gave a small noise in appreciation. Marshall had been led to believe by her reaction to him biting her lip that it wasn't really her thing, so was still a little hesitant as he shifted down and bit her neck, dragging his tongue over the spot immediately after. One of Fionna's hands laced into his hair as he did so and she arched her neck, and Marshall finally felt as if he was getting a hang of how he needed to go about this. She wasn't a porcelain doll, but she ain't a Raggedy Andy either. Somewhere in between. He wasn't the sort of guy who continually asked ' Is this okay?' preferring to judge based on reactions. But in this case, a mistake could be fatal. Almost literally.
' Tell me if you don't like it, 'kay?' He muttered into the crook between her neck and her shoulder, noticing there was a group of three moles in the shape of a triangle there. Fionna nodded and her hair felt soft and fluffy against the side of his face. All the sensations and scents and stimulation her very prescence was giving off to him made him feel slightly drunk, like he had just had several tequila shots. The haze made him want to give in to that raging energy ball all the more, but when his hands skimmed her back she felt so soft and warm that he believed it would tear her to bits with its ferocity. He couldn't just dissolve into her, not yet, his actions had to remain conscious.
Fionna wasn't as worried when she felt Marshall undo the strap of her bra this time, but she still didn't like the way he stared after he pushed her down onto the covers, so that he was supended above her on all fours. It made her feel all exposed and vulnerable, and seeing as he was still pretty much fully clothed it also didn't seem fair.

It took Marshall-lee a minute to realise Fionna was undoing his shirt because he was so absorbed with her breasts. Glob, those thing were perfect. He had never thought such a thing was possible because, y'know, boobs. All of them were perfect because of what they were. He had been proven wrong though, and was continuing to be proven wrong by the example of complete and utter faultlessness in front of him. They were made for him, they must have been.
When he did realise however, he sat back a little and helped her push the sleeves off his arms, casting it aside before leaning over and kissing her again. The feeling of his hands on her chest reminded Fionna of when he had broken into her room, but seeing as her arms weren't restrained this time she was able to brush the confusing memory aside. It did feel good though, and she accidentally bit Marshall's lip when he ran his thumb lightly over the tip of one of her nipples. He didn't seem to mind though, instead humming happily as his hand ghosted further down her body and he broke away from her lips to work on her neck again.
They had seemed to find a sort of rhythm thankfully, and Fionna was glad that she was finally starting to relax as Marshall unclipped her garter straps and took off her boots and socks, running his hands up her calves to her thighs. The way she touched him was more tentative then his purposeful movements, because while she could admire the way his body looked she wasn't exactly sure what she should do with it. She was mostly content just to hold on to him at the moment and he didn't seem to find anything wrong with that.
Fionna absently noticed a characteristic bulge in the crotch of his jeans and her relaxation disappeared rather quickly as she remembered a line from that book Cake had given her to read:

The first time a girl has sex, it can be a little painful. The vagina is a muscle, and like all muscles, needs to be stretched. This will happen during sex and sometimes the first few times it can be overstretched, like any other muscle.

It wasn't like she could tell much given he still had his pants on, but his, uhm... It didn't look exactly small. The knowledge had been running in the back of her mind and firing her nerves, but now that she was really thinking about it, it made her want to cringe into a little ball so she wouldn't have to find out whether it would hurt.
She could take pain, that was no problem. It was just being hurt there? Of all places? Given how badly period cramps ached she didn't want to know how badly overstretched vagina could ache. She hadn't even known it was a muscle until she read the book (it was obvious in retrospect though, a baby wasn't gonna just fall out of there)
Her train of thought was scrambled when Marshall's mouth found it's way onto her chest and he started to suck, licking and prodding at the pinkish nub. A loud, wanton moan escaped from her throat before she could stop it and she blushed dramatically, mortified by the unwarranted noise. Marshall growled appreciatively, his hands finding their way up her skirt and starting to tug impatiently on her shorts. She allowed him to pull them down her legs ( Gob, he fuckin' loved her legs. They were so sexy. She was so sexy. All of her. Everything.) then yelped in surprise when Marshall followed by instantly removing her skirt and underwear, every remaining scrap of material gone in a flash. It kind of made her think that the shopping expedition earlier had been a little pointless, like wrapping a present for an overexcited child. They don't care about the effort you put into tying the bow.

She tried to pull her legs in and curl up automatically, but Marshall's waist was between her knees so she couldn't. Fionna started to panic when one of his hands skimmed up the exposed skin of her thigh, and she quickly wound her fingers into his hair and tugged hard to get his attention.
' M-marshall, slow down!' She stammered breathlessly, and his fingers stopped their ascent literally inches from their goal. He lifted his head from her chest and Fionna noticed that he was panting, which sort of shocked her. Marshall-lee was technically dead, and had said to her before that the only reason he breathed in the first place was for the sake of scent. But she could see his shoulders rise and fall and his chest expanding and she suddenly had an inkling as to just how badly she was affecting him.
The both just stared at each other for a short time, then Marshall pushed himself off of her and back onto his knees, biting his lip at how the movement caused his jeans a moment of uncomfortable and frustrating friction. Fionna immediately closed her legs ( She was not letting him stare at that). Marshall-lee pressed the base of his left palm into his eye for a second and rubbed, trying to expand his thought process beyond 'fuck her.'
Gob, he hadn't realised it would be so difficult. He should have, but he had thought it would've been convincing her that was going to be hard. The actual sex part had happened a million times in his head but obviously, his fantasies didn't allow for the realism of making a mistake.
'.. c'mere.' He murmured after a second, sitting back and opening his arms, making a come hither gesture with his hands. Fionna blinked at him, randomly appreciating the muted, though slightly ominous glow of his dark red eyes, then got onto her hands and knees and crawled towards him. His hands stroked down her arms, then underneath them to her ribs.
' Turn around.' He told her and she did so, a little confused as to what he wanted.

His arms wrapped around her chest just below her breasts and tugged her down against him, so that she was leaning on him with his legs splayed on either side of her. Her angle was such that only her upper back was in contact with him. Then Marshall ducked his head and kissed her cheek, then down her neck and the top of her left shoulder. Fionna inhaled through her nose and mewled slightly when his hands cupped her boobs and he started kneading at them, rolling his palms over her nipples. The sensation made her arch her back, pressing her chest more firmly into his hands, and Marshall bit her neck softly as he took that as a cue to let his right hand drift lower again.

He settled for just drawing circles in her pubic hair for a little while, watching out for any complaints on her behalf. But then her shoulders rolled and her body shivered and she gave a low noise of impatience that went straight from his ears to his groin. He slowly ran his fingers down, waiting for the characteristic twitch n' hitch that meant he had found the right spot.
Fionna couldn't help but groan between her teeth when he started to stroke and rub, his touch skilled and confident, arousing her almost faster than she could herself. Because he was still playing with her breast, pretty soon her body felt as if a million tiny pins were pricking the inside of her skin over and over again, and she cried out loudly at the overstimulation, too caught up to be embarrassed.
' Tell me when you're gonna cum, baby.' Marshall murmured, then drew his tongue around the shell of her ear and bit the lobe again. Fionna couldn't reply with words, only sounds as he moved even faster, collecting the liquid that was spilling from her and using it to make his movements smoother and altogether more maddening. She recognised the beginning of her climax and Marshall felt her start to tense up, her body shivering and making her pant shallowly.
' A-aahh, J-just a little more... Marshall...' He growled under his breath and bit the top of her shoulder, hard. When she said his name like that... damn. His fangs pricked her skin but incredibly, the regular lust overrided the blood lust and prevented the flavour of the first real human blood he had ever tasted from sending him into a frenzy. It was a fact he would only realise later, and one he would keep to himself, because it sincerely made him more frightened of how strong the imprinting was.

The shock of pain catapulted Fionna to the top much faster than she was expecting and she screamed as she came, grabbing onto Marshall's legs on either side of her and digging her nails into the fabric. Her back snapped inwards and her head backwards, and Marshall was able to watch her expression as she arched over his shoulder, her mouth open and her face so ecstatic it almost looked like pain. Just her expression alone was nearly enough for him to follow her all too quickly.
She was in the middle of the aftershocks when he moved out from behind her and laid her down, so she didn't protest. But he saw her watching him through half-lidded eyes as he undid his jeans, wincing at the way the fabric pulled (he was so fucking hard, it wasn't funny)
She looked so exhausted that he didn't notice she was worried until he had gotten rid of his jockeys and had lain down over her again, suspending himself above her on his elbows. She was recovering quite quickly and even though she was still gasping heavily, she was still alert and eyeing him apprehensively as she wrapped her arms around his back.
' This isn't gonna be painful, r-right?' She mumbled, licking her lips and blinking rapidly.
' Maybe. Tell me if it's too much.' Marshall kissed her once, to calm himself, before he raised back up and pushed her legs further apart with one hand.

' U-Uh.' She groaned shortly, cutting herself off and squeezing her eyes shut as he started to press into her. Her thighs were shaking and a flash of heat brought an instant slick of sweat across the surface of her skin. Marshall almost wanted to stop, to give her a little time to adjust, but no matter how much he thought that his body ignored his intentions. Ah. Gob, had he ever fucked a virgin before? She was soft and he could move easily, which assured him that she was indeed prepared to take him, but it was still so tight. Cheesus rice.
Keep it together, Marshall. Keep it t-... Uhh...
He was all the way in before her realised he'd forgotten a condom, or any sort of birth control really, and he cursed mentally. But his vague concern changed directions and became more focused when he looked at Fionna and saw that there were tears welling up beneath her tightly closed lashes, her brow screwed up and her lower lip shaking.
' It h-hurts' She squeaked, her words interrupted by a breath so shaky it was almost a hiccup. Marshall didn't say anything, all of his concentration directed towards not moving, not loosing control and humping her like a dog. He kissed her cheek, almost in apology, before he rocked his hips slowly and almost literally saw stars burst in front of his eyes. Gob, give me strength.
Fionna made a small noise in discomfort again and her hands clenched on his back, curling into fists rather than digging her nails in. The sensation was so strange all by itself that she wasn't sure whether she actually liked it or not, and combined with the strong, strained ache near her entrance it was unpleasant at the very least. However, as Marshall continued the sluggish movement, having to contain that explosive energy ball now more than ever, she realised that if the vagina was a muscle, as well as being stretched, it could also be relaxed. And when she finally figured out exactly how to do that, she exhaled loudly and clutched him to her tighter as the pain lessened and she decided she actually did quite like the feeling of him inside of her.

' You okay?' Marshall murmured curtly into her ear, before grunting slighty as she clenched and relaxed again, his shoulders shuddering for a second. The words 'hold on' were running like a mantra through his head, a steady chant matching the pump of her heartbeat. But it was getting fainter.
' Mm.' She assented and Marshall tentatively picked up the pace, the fact she had already cum meaning there was enough lubrication that he knew it wouldn't be scraping her roughly. However, with the speed his iron-grasp over his desire began slipping, and Fionna gripped him worriedly as he hit her hard enough to make her tighten in surprise and she yelped at the shock of pain when he dragged himself back out.
' M- Ah, Marshall-lee!' Her cry was more alarmed than aroused and he could hear that, but the unbelievable stimulation, stronger than any he'd had before, stopped him from slowing down or easing up. He tried, but it would've taken a herculean amount of effort and when he was so close and had been waiting so fucking long he just didn't have it in him.
I'm sorry, Fi.

Fionna mewled frantically at the pain, clawing desperately at his back to try and get him to stall, but nothing worked so she just focused on trying to stay relaxed as her body jerked with each hard, jagged thrust. But it was bringing tears to her eyes and all she could think, all she wanted was for it to stop.
Marshall vaguely told himself he ought to pull out, but when he was loosing all restraint so thoroughly it was almost a laughable notion to even attempt it. And then every notion, all of his thoughts and emotions, his entire self was obliterated as he came in a empty white-noise headspace where there was nothing but all-consuming pleasure.
Fionna cried out weakly at a final, forceful thrust and then made a tiny noise in surprise at the sudden burst of liquid heat deep within her in a place she didn't know existed. Marshall had yelled out something or other but she was too preoccupied with the pain to figure out what it was.

Marshall-lee gasped heavily, his shoulders shaking and straining to keep him aloft above her and sweat beading on his forehead as he rode out the aftershock, feeling throughout his entire body like he was drowning in white-hot gold. Fucking Nirvana indeed. Holy hell.
It took him a while to find himself again and make it back to reality, but as he pulled out he recognised an odd, empty feeling in his stomach as a sense of dread. He only realised his vision had blurred when it refocused as he looked up.
Fionna was biting the side of her hand as he freed himself from her tender flesh, her body trembling and a tear trickling its way from the outer corner of her eye as she stared at the ceiling, where it was absorbed by his sheets.
Oh, crap.

Author's note: Hm. Yeah. This was difficult to write. This arc will continue next chapter but then I'll be mixing it up again, probs. So, hang on, it doesn't stay all sad an' Oh-God-So-Cringe-Please-Kill-Me, promise. Oh and yaaaay, more than 100 reviews. Thank you all so much for reading, we're up to the sexytimes at least. Even if they're terrible and awkward right now. I'm so sorry.

-WRA

Guest reviews: ( I missed last chapter's oops)
blashfoiweagawio: I'm glad you like Femme, but she ain't actually an OC, she's a genderbend of a character from the comic book canon. His name is Guy and Guygum is a semi canonical relationship in that they were both kinda like I would enjoy being all up in your grill but it never really happened. :( So I made it happen, shoot me.

Guest: I enjoy rocking serious socks, they ought to lighten up and have fun more often. Thank you for the review!

TooLazyToLogin: But not too lazy to leave a review. Thanks!