Bill comes back at least once every week when everyone's gone or asleep and every time they have some pretty good sex. Dipper enjoys not having to rely as much on his left hand as he used to what with Bill having seemingly gotten addicted to the pleasurable activity. What's so great about having sex with Bill is how every time he swings by for more, there's something new he wants to try out. Sex is thus never boring – not that it would otherwise be.

This time isn't quite like all the others. Bill appeared as soon as everyone left the house and things got down and dirty quickly. They were on each other, touching and kissing what little flesh they could reach before they began tearing off their clothes. This isn't particularly uncommon, though. At times, when Dipper is feeling stressed because of University or life in general, he doesn't allow the time for Bill to announce a new sexual discovery he would like to try. Rather, they end up having sex fairly quickly. It's a sort of release for Dipper. Bill is fine with it. He typically says what he would like to try after they're done and makes Dipper promise to make it happen the next time.

But, as previously mentioned, this time isn't quite like the others. He doesn't know if it has to do with the stress of finals or the unclear expectations of his teachers, but Dipper feels angry and frustrated so much so he manhandles Bill a little too roughly. And though he notices this, Dipper struggles to make an effort to stop – and this might have to do with more than one thing. As much as being rough and, frankly, aggressive with Bill helps release his pent up frustration, Dipper knows it's bad but the demon seems to be enjoying it. The sounds he pulls from him are far more erotic and sinful than any other time they fucked.

Dipper pushes Bill against the bed and grinds their hips together. Bill gasps and thrusts up to increase the pleasurable pressure and moans and whimpers pathetically with want. Dipper grabs the demon's wrists and pins them above his head before diving down and latching his lips onto the sensitive flesh of Bill's neck. Again, the reactions he pulls from the demon are surprisingly erotic and lustful – like he's never been more turned on in his whole life – which encourages Dipper to give into his primal anger and abandon control.

However, a particularly loud groan from Bill snaps Dipper out of his trance mostly because it also sort of sounded like a scream. Dipper blinks stupidly for a moment and suddenly realises his mouth is filled with the taste of metal. He glances down at the patch of skin he was sure he was sucking a hickey into only to find teeth marks from which blood is pouring. Dipper immediately releases Bill and backs off, horrified by what he has done.

"Bill—I'm so sorry!" He apologises, his voice shaking, "I-I don't—I don't know what came over me—"

"More." Bill says and it takes a moment to process for Dipper who stares at him as though he misheard.

"What?" He asks.

"Damn it, kid!" Bill frowns, his cheeks reddening as he looks away, "You know I don't like dirty talk!"

"This isn't that," Dipper says in confusion, "I'm not sure I heard you properly."

Bill makes a sound to signal his annoyance. He tears his gaze from the wall and looks at Dipper straight in the eyes, "I want more." He says seriously though his cheeks still redden all the more as he goes on, "I like it when you're rough, when you bite me like that…I like it a lot…"

Dipper blushes as well. He was so afraid Bill would be angry because he hurt him though it seems to have had the opposite effect. Bill raises his arms to lay above his head and exposes his bleeding neck. His eyes are still locked with Dipper's which is making this more sensual. He bites his lower lip and then says:

"Make me scream."

All restraint Dipper once had vanishes with the three previously uttered words. His mouth is back on Bill's neck, licking the wound a bit before moving on to make a new one while his hands desperately roam to the demon's erection. His hand grasps the erected member and Dipper is surprised to see – to feel just how much Bill finds the pain sexy. He bucks his hips desperately into Dipper's hand and cries out when his neck is bitten roughly again.

"Pine Tree—" he whines impatiently.

"God you sound so sexy…" Dipper breathes as he pumps Bill's dick.

"A-ahn!" Bill moans and gasps, "Tighter!" He begs, "Your hand—"

Dipper hesitates but complies with Bill's plea. He's sure this would be painful to anyone else but Bill relishes at the pain and moans much louder. He bucks his hips in time with Dipper's hand, tangling his own fingers in the bedsheets beneath. The filthiest things start to pour out of Bill's mouth and, like every other time, he doesn't seem to realise it. It makes Dipper's dick harder. God he loves Bill's voice.

And just like that, Bill cums with a thrust of his hips and a divine shout of ecstasy. Dipper releases his soften cock and looks the demon over. His cheeks are flushed pink and his mouth is partially open. His lips are dark from having been bitten. The more Dipper takes in the slightest details of Bill, the more he wants to kiss him.

"Hey, Bill," Dipper nudges playfully, "Don't fall asleep on me. I need to get off too."

Bill opens his eyes lazily and smirks at Dipper, "You always cum last, don't you?" he teases.

"Because I actually have endurance." Dipper responds cheekily.

Bill sticks his tongue out and pushes Dipper off him. Dipper makes a sound of distress as he thinks Bill is done and he'll have to content himself with his left hand. However, the demon gets on all fours and lowers his upper body closer to the mattress and exposes his oh so perfect ass. Dipper's heart skips a beat at the display. Bill seems to have been favouring doggy-style lately but Dipper's not complaining.

"What are you waiting for?" Bill purrs with a knowing smirk, "Didn't I say to make me scream?"

Bill knows just how to drive Dipper crazy. His words, his tones, and his expressions are always on point. Dipper pounces the demon, spreading his legs open to kneel more comfortably between them and grinds his crotch against his ass. Bill whines and pushes back greedily. Dipper smirks and pushes the former's ass and his crotch apart in favour of stretching Bill's entrance. Rather than find this tube of lube, Dipper decides his spit will make a suitable replacement – especially since Bill is craving the pain.

He spits on his three fingers and quickly penetrates him with the first digit. Bill keens in pleasure, burying his face in the mattress and biting at it to control the sounds pouring from his lips. Dipper reaches over and tugs on the demon's blond hair to lift his head. Dipper's mouth is next to Bill's ear when he whispers:

"Don't forget, I like hearing you, Bill."

The demon's pupils dilate with lust. His face is flushed red and he almost seems like he's stuck in this strange trance of ecstasy. He nonetheless nods and makes a relative effort to keep from muffling his moans when Dipper penetrates him roughly with a second finger. The sounds Bill is making are otherworldly and arousing beyond description. Dipper doesn't know how long he can keep this up before he gives in to his primal need to fuck Bill's brains out. However, Bill's the one who caves first.

"Come on, Pine Tree!" He begs breathlessly, his voice trembling with desire, "I can't—I need it!"

Dipper smirks and decides to milk the situation for all its worth. "Still got one more finger to go, Bill." He says with a teasing tone, "I got to take my time and stretch you good… you know what would make me go faster, though?"

Bill's eyes widen and he glares back at Dipper, looking over his shoulder, "That's cheap, Pine Tree!" Bill snaps though his accusation is quickly followed by a series of lecherous moans.

"Is it?" Dipper hums lowly with a grin and, after a moment of a lack of response, he adds: "Well, what's it going to be?"

"Y-you wouldn't even be able to last all that long!" Bill says between moans and his uncertainty is detectable.

"Are you willing to risk it?" Dipper grins.

"God damn it, Pine Tree!" He snaps and part of his intensity is because Dipper's fingers jabbed his prostate, "Fine! Please hurt and fuck me! I need your cock inside me!"

Dipper is mildly disappointed with the lack of arousal the words provide him with but stipulates it might have something to do with Bill's evident annoyance. This being said, Dipper doesn't have the will to resist any longer. He pulls his fingers out, earning a breathy gasp from the demon, and quickly replaces them with his cock. Bill cries out in pleasurable pain while Dipper groans in minor discomfort. He reckons he might have to pull out and add a little lube for himself or stretch Bill a little more. Bill's ass is so tight around Dipper's prick it's a bit suffocating.

"Pine Tree!" Bill cries and pushes back against his cock, "Move!"

Dipper hesitates but decides to give it a shot. If he's really not comfortable, he'll pull out and add a bit of lube. He grasps Bill's waist tightly with his hands and begins thrusting slowly. The sensation isn't particularly pleasurably at first but, with the spread of precum, moving isn't as much of a chore. Bill, on the other hand, has never been pleasured to such a degree. He's clutching at the bed covers and desperately meeting all of Dipper's thrusts with vigour and need. It takes time for Dipper to match him in intensity but, when he does, all Bill can do is scream his bliss to the heavens. Skin smacking against skin, and cries of absolute ecstasy are likely the only sounds that fill the house. They're the only sounds that matter to Dipper.

He pounds roughly into Bill's ass and the demon screams and cries out far louder than he ever has. Dipper knows he's reached his prostate and, by the clenching of Bill's ass, he knows he's going to cum again soon. Dipper considers reaching around and helping Bill finish with his hand but decides against it. He wants to see if he can get the demon to cum untouched. This decision permits Bill to begin displaying his level of endurance which Dipper is beginning to think is a bad decision because he's just about ready to climax. He's about to give up on getting the demon to cum untouched when Bill's ass suddenly gets tighter and he lets out one of his lovely climaxing cries of pure bliss. The sudden tightness is enough to get Dipper to cum deep inside Bill's ass and it's mind numbingly satisfying.

Dipper pulls out and nearly collapses on Bill who's lying on his stomach. He's clutching the bed covers and staring emptily in Dipper's general direction while breathing heavily. His pupils are so dilated they seem to have simply become black. Dipper tilts his head a little, focusing on something he otherwise would have missed. His heart skips a beat as he pushes himself up with his forearms and grazes Bill's cheek gently.

"Oh my god, Bill, I'm so, so sorry!" He says and guilt churns at the pit of his stomach. He can't believe himself.

Bill snaps out of it and looks at Dipper in confusion, "For what…?" he asks slowly.

Dipper frowns and bites his lower lip, "I knew I was going to hurt you." He reproaches himself.

"What are you talking about?" Bill asks, utterly lost.

"You're crying." Dipper says softly.

Bill confusingly dabs his cheeks with his fingers. He blushes furiously upon finding his tears and promptly hides his face in Dipper's nearby pillow.

"I'm so sorry." Dipper apologises again.

"Shut up." Bill hisses though it comes out less aggressive because it's muffled.

Dipper flinches and looks away pathetically. "You have every right to be mad…" he mumbles, "I was careless, I have more experience than you, I should have—"

"Oh my god, Pine Tree!" Bill snaps and shoves the pillow in Dipper's face, "I'm not mad!"

"But you're crying—" Dipper says but quickly interrupts himself and stares at Bill. It takes him a moment to understand the silent message and his eyes widen in surprise when he does, "That…that good?"

"Oh shut up!" Bill hisses and shoves Dipper.

"I made you cry because I was so good?" Dipper persists with a goofy grin on his face. How can he not be proud in that case?

"If I still had my magic, I'd kill you." Bill grumbles and shifts on the bed.

"Oh? And what are you going to do instead?" Dipper purrs.

Bill frowns and pulls Dipper down onto the mattress. Dipper laughs and Bill rolls his eyes, cuddling closer to his stupid human. "I want to cuddle." He mumbles and Dipper obliges.

They fall asleep as such and, the next day, Dipper wakes up alone in his bed as usual. His room is cleaned and there's not even the slightest drop of sweat or cum anywhere. He grins at Bill's tidiness and shakes his head. Some would argue having a demon as a friend with benefits is a bad idea but Dipper would counter that it's the best decision he's ever made.