Although the characters are not canonically underage, please be aware this fic place in a high school AU, so turn back now if you are uncomfortable with this.
Aster is based on 2P (blueberry) Alastor, and is depicted as Alastor's nonbinary sibling in this fic, hence they/them pronouns.
Also, this is my first time writing something so dirty, please forgive me lol. Enjoy this sinful abomination ( ͡° ͜ʖ ͡°)
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It was noisy.
It was so fucking noisy.
Aster slumped over the kitchen table and groaned. There were too many drunk people around. Even their brother had been drinking, and while Alastor was more relaxed and friendly a after a few drinks, Aster didn't like the idea of the only person at the party they trusted getting wasted.
Why did they think this was a good idea? The only parties Aster had ever been to were birthday parties when they were a child, the kind of parties that involved balloons and cake. Not booze and debauchery. This was way out of their comfort zone.
Aster needed to get away, even if just for five minutes.
Leaving Alastor to mingle with the other party-goers, Aster quietly slipped out of the kitchen and upstairs, stepping over a couple making out on the floor on their way.
There were several doors to choose from upstairs. Aster didn't care where they led to, selecting the only one that actually sounded quiet on the other side. And it was. Aster quickly dashed inside and closed the door, immediately relaxing with a sigh of relief. Peace and quiet at last.
"Hey, buddy. Didn't expect to see you here."
Aster whirled around to see Angel Dust lounging on a bed in the dim light of a lamp sitting on the nightstand. But he was completely naked.
"Oh my goodness, I'm so sorry," they squeaked, quickly averting their gaze and turning bright red. "I didn't see anything, I promise."
Angel chuckled. "Nothing that hasn't been on public display already. Were you looking for the bathroom or something?"
"N-No, I... I just wanted somewhere quiet to rest for a few minutes."
"Well, if you don't mind my company, you can hang out here with me." Angel patted the empty side of the bed as an invitation.
Aster hesitated, still unable to look at the spider demon. "If you don't mind me asking, why are you...?" They trailed off, blushing again.
"Naked?" Angel laughed. "A hookup, what else?"
Aster wasn't sure if he was being serious or not.
"You haven't been to many parties, have you?" Angel grinned. "I can put my clothes back on if you want."
"Y-Yes please..."
Within half a minute, Angel was clothed again in his usual shirt and shorts, and Aster finally felt comfortable enough to approach him. As they sat on the bed beside him, Aster couldn't help but notice a used condom had been carelessly tossed aside and was now inches away from them.
Angel saw them recoiling in disgust and quickly removed the condom from where it lay, throwing it into a far corner of the room. "Sorry about that," he chuckled, deciding he would dispose of it properly later.
Aster's curiosity got the better of them. "What's it like?" They paused, realising what they just asked. "I'm sorry, that was a really intrusive question."
Angel gave a friendly smile. "You mean sex?"
Aster stuttered nervously. "Well, um... y-yeah. I, uh, I've never actually... well..."
"You're a virgin? That's no biggie," said Angel casually. "Everyone is always in such a hurry to get laid, but there's no rush, you know?"
Aster pondered for a second, heart racing, wondering if they dared to ask. "I... sorta want to try it..."
"What, with me?" Angel teased. He had only meant it as a joke, but his smile faded when he saw a shy blush appear on Aster's face, and when they didn't say a single word, he knew he was correct.
Angel ran a hand through his hair nervously, unsure how to respond. Aster whined and buried their head in their hands, embarrassed beyond belief that they had even started such a conversation.
"I'm sorry!" they mumbled into their hands. "I... I just think you're really hot, and-" They stopped and whimpered, realising they were only digging themself deeper.
Angel laughed. "Is that so?"
He rolled over and pushed Aster down onto the bed, a small gasp escaping the blue-haired demon.
"Angel...?"
Angel leaned closer to whisper in Aster's ear. "You still wanna try it with me?"
The tickle of Angel's warm breath against Aster's ear caused a shudder of pleasure to run through them. "Y-Yes... I just wasn't expecting that."
The spider demon slowly moved his head to meet Aster's lips. The blue-haired demon tensed up, their inexperience obvious to Angel, who pulled away and looked into their eyes.
"Are you sure you're ok with this?" he asked, his tone serious.
Aster gave a quick nod, reaching up to caress Angel's soft hair. He leaned in and kissed Aster again, this time giving little flicks of his tongue over their lips. Angel could tell they liked it by their little shudders and decided to go a bit further, pushing Aster's lips apart with his tongue and entering their mouth.
Aster gave a little moan, heart pounding faster, surprised at how nice Angel's warm tongue felt. They tried to imitate his experienced movements as best as possible, but they found it incredibly difficult to concentrate when their mind was foggy with arousal.
Through the haze of lust, Aster suddenly became aware of what was happening to them down below and quickly pulled away from the kiss in a panic.
"Angel, wait," said Aster breathlessly, but they could tell by the mischievous grin on Angel's face that he had already noticed.
"Got a boner?" he chuckled softly. "No need to be shy about it. So do I."
Aster blinked in surprise, expecting Angel to comment on how they were 'actually a boy', but no such comment was made, and they began to feel a deeper level of trust in Angel.
"Tell me what you want," Angel whispered.
Aster swallowed, the seductive sound of Angel's voice making them more aroused by the second. "I... I don't know. Like I said, I've never done anything like this before." They shyly averted their gaze, wanting it so badly, but unsure what 'it' even was.
Angel slowly ran a hand across Aster's chest, across their stomach, creeping lower and lower until his hand was hovering over the buckle on their trousers. "Can I undress you?"
Aster hesitated. Nobody outside of their immediate family had ever seen them naked.
"You can say no," Angel continued. "If you want to stop, just tell me."
"I... I want to... keep going..." Aster could barely get the words out through soft panting, unaware that their hips had begun moving, brushing their firm crotch against Angel's hand.
That was all Angel needed to hear. He gently unbuckled Aster's trousers with one set of hands while sliding them off with a second pair of hands, finally casting them onto the floor. Angel smirked at the sight of their fully erect cock.
"Want me to suck it?"
Aster's eyes widened, shocked at the casual bluntness of Angel's question. Angel noticed this and laughed.
"You really are new to this, aren't you?" he teased, running a finger along the underside of Aster's firmness. "It's cute."
Aster found themself craving more of Angel's gentle touch, their shyness giving way to desire. "Please... s-suck my..."
Angel smiled and nodded, and before Aster could ever utter the last word, he bent over and took the full length of Aster's virgin cock into his mouth.
Aster held back a surprised moan, a tiny voice in their head reminding them that other people were in the house. Angel could tell from experience that Aster was holding back, and quickened the pace of his mouth up and down their shaft while teasing the head with his tongue, trying to encourage Aster to express their pleasure more openly.
It worked. Aster sharply gasped as Angel sped up, clutching the bedsheets and panting wildly, legs trembling, tears forming in their eyes. It felt so good, they could barely stand it.
Angel lifted his head, swirling his tongue around Aster's sensitive tip as he pulled them out of his mouth. "Is this ok?"
Aster whimpered desperately, their face flushed a deep red. "P-Please, Angel... don't stop..."
Angel smirked. "No problem. Just let me know when you're about to cum, alright?"
Aster opened their mouth to respond, only to let out another shaky gasp as Angel resumed licking and teasing with his skilled tongue. They weren't sure how much longer they would last; all these sensations were so new, Aster had no definite way of knowing how close they were to orgasm. It was as if Angel had complete control over what their body was doing, and in a way, that turned them on even more.
It didn't take long before climax struck like a shockwave through their entire body. Aster found they no longer cared who could hear as they cried out in ecstasy, shooting down Angel's throat.
"Damn, that was quick," he commented, wiping traces of Aster's seed from his lips.
Aster's ears drooped. "S-Sorry..."
"Hey, it's alright," Angel assured. "How was that for you?"
A huge smile crept across Aster's face, still slightly delirious from their orgasm. "It felt really good. But I'm really sorry I, um, finished in your mouth."
He gave a friendly laugh. "Don't worry about it." An idea suddenly popped into his mind. "Although, if you want to make up for it, there is something you can do."
"What is it?"
Angel began to unbutton his shorts, freeing his cock which was now twitching with arousal. He noticed Aster's wide-eyed expression and grinned.
"Do you wanna try giving the blowjob this time?"
Angel didn't need to ask twice. Aster took hold of his length, leaned over and tentatively gave the shaft an experimental lick with the tip of their tongue, looking up at the spider demon for approval.
Angel chuckled. "It's gonna take a bit more than that, babe."
Aster gave a nervous giggle and began licking Angel's tip like a lollipop, trying to ease themself into it.
"Try sliding it into your mouth," Angel encouraged gently. "Like how I did it."
Aster hesitated "Ok, but... please don't... in my mouth... you know..."
Angel tilted his head in confusion. Then it clicked. "Oh, cum?"
They winced, once again unprepared for Angel's blunt choice of words, but nodded.
"Don't worry, I'll make sure I pull out before that happens," he promised, ruffling their hair affectionately.
Aster visibly relaxed, slowly taking Angel's cock into their mouth, but only managed about halfway before the tip hit the back of their throat and they coughed in surprise.
"Careful," said Angel. "Don't push yourself, ok?"
They tried again, this time gently running their lips up and down as much of Angel's length as they could manage, simultaneously swirling their tongue around the head just like Angel had done.
"That's it, just like that... you're doing great," Angel praised, gently rocking his hips to match the motions of Aster's mouth, cradling their head at the same time. "You're a natural at this."
Aster's heart swelled with pride, finally getting into the rhythm. Angel began to moan softly, and hearing his enjoyment made Aster hard again. They didn't realise it could feel this good to please someone else.
"Aster!"
They stopped. That wasn't Angel's voice.
"Aster! Where are you?"
Aster bolted upright. "F-Fuck! That's Alastor! He's looking for me!"
"Shit, seriously?" Angel complained. "Your brother is a fucking boner killer. I'm gonna murder him at school on Monday."
"What?!" Aster cried. "You can't tell him what we were doing!"
"I can't? That's no fun," said Angel mischievously. "Alright, I promise I won't tell."
Aster breathed a sigh of relief. "Th-Thank you..."
"Aster! Are you still here?"
The blue-haired demon quickly put their trousers back on in a panic. "I guess I'd better go. Sorry."
"Catch you at school, babe." Angel gave Aster one last peck on the cheek. "Let's finish this another time, alright?"
Aster gave an enthusiastic nod before dashing out the door to find their brother. Thankfully, their erection had subsided by the time they spotted Alastor across the hall.
"Alastor!" they called out. "I'm over here!"
The red-haired demon turned around. "There you are! I was looking all over for you." Alastor narrowed his eyes, noticing his sibling's flushed face and strange breathing. "What have you been doing?"
Aster couldn't look directly at their brother. "Um... nothing."
To Aster's relief, Alastor was too tired and too tipsy to question any further.
"Very well," he yawned. "It's getting late. We should go home before mother begins to worry about us."
"Yeah," Aster agreed, happy to be leaving the noisy booze-fuelled party at last.
"So," Alastor continued to speak as the two siblings made their way out into the cold night, "did you enjoy your first party?"
Aster's heart beat faster at the thought of what they did with Angel Dust, thankful that the cold evening air and nighttime darkness prevented any blush from being visible on their face.
"Yes," they admitted with a shy smile. "I suppose I did."