James' stepsister Lily. And she's equal parts pissed and... horny?

"I'm trying to get off in my room and you're moo... -ing...?" Lily's voice trailed off as she took in the sight before her: Her brother was lying on his back on his bed, so far so normal, but between his legs...

"Holy shit, is that an udder?!" Lily gasped, mouth falling open. Her eyes were fixed on James' cock-like teats. This shouldn't be hot, but she'd been so close and her pussy felt so empty...

"Oh god, no, please don't look!" James screamed, desperately trying to pull the milk-soaked sheets over his bulging udder. In his frantic movement, his leg knocked into his udder, thin streams of milk spurting out of the left-most teats. James doubled over in a mix of pleasure and pain. Mostly pain, though.

When he had recovered, he found his stepsister standing next to the bed, her face inches from his udder, curiously inspecting it. Her questing fingers sent shivers through his body, sapping all his strength - James collapsed onto his back.

"Wow, it's actually real..." Lily whispered, but James barely heard her through his **** gasping.

"Do you really give milk?"
"NGAAAAAH!"

James' world went white as he felt his stepsisters hot lips wrap around one of his teats and start sucking. He felt his milk spurt out the stiff protrusion, and overwhelming pleasure radiated first through his udder, then through his whole body. It seemed to pool in his chest and throat, but James was barely able to think, let alone focus on anything but Lily's insistent suction... after suction... after suction.

After what felt like an eternity, the sucking stopped and James heard his sister say: "Listen, bro, you interrupted my alone time, I think it's only fair if you help me out."

"What are you--OH GOD!"

Before James could protest or even process what was happening, Lily had climbed on the bed, straddled his udder and lined up the teat she had been sucking on with her dripping pussy. Then, with one smooth movement, she sat down and shoved the erect meat into her squishing honeypot. The weight of his sister **** more milk out of his udder, thin streams shooting out of the three unoccupied teats, the fourth squirting its fluids into Lily's twitching snatch.

"Aaannh, it feels so much better than my dildo!" Lily squealed, "It's so warm!"

"Oh fuck, Lily! This is--ngh, no! It's too sensitive!"

"Ooonnnh, your milk is so hot inside me," Lily moaned, gyrating her hips on top of James' udder, "and that teat is so thick!"

"Your pussy... it's so... I can't--oh gooood!" James rambled, overwhelmed by the feelings. He could feel his step-sister's twitching pussy massaging his cock-like teat, Lily's folds wrapping tightly around the sensitive flesh. The sensations were sapping his strength, but even if he could, James would not have pushed Lily of himself - his udder simply felt too good. His step-sister's soft thighs caressed it with every movement, sending little shudders of pleasure through his whole body, one of his milk-slickened teats was sandwiched between her ass cheeks and the one in her pussy... James felt as if it was melting. His milk mixed with Lily's juices and with every circle of her hips, lewd squelching noises filled his room.

"Amazing... it's so fucking big..." she gasped, beginning to bounce up and down on James' udder. Every time she dropped her tight bubble butt on the slowly shrinking mound, four spurts of milk were **** out of his teats, the one shooting into her snatch causing her to moan uncontrollably. Every time she rose, the suction of her drooling pussy pulled on his teat and a bigger stream hit her deepest parts. Lily's cunt was gripping James' meat so tightly that very little fluid was getting out - little by little, her belly started distending from all the milk inside her womb. The insistent pulling on his sensitive flesh nearly made James black out, but his udder wasn't the only source of pleasure; in fact, the sensations in his chest and neck intensified until James couldn't take it anymore. He needed to touch his pecs.

Forcing his weakened arms to move, he lifted his hands and let them fall onto his chest. But the pecs they landed on weren't like James expected them to be. Instead, he could feel his fingers sinking into pliant flesh, bloated, engorged nipples and areolas pressing into his palms. James didn't care about the changes, though: All he wanted was for the feeling to completely overtake his being. He pulled and pinched his nipples, squealing as thick milk spurted from them as well. Wait... squealing?

"Oh shit--Aanh! My voice, it's... nnnnhmooo..."

"Fuck, Jamie, you sound so--ah! Sexy! Like Calista Lovelace!" Lily exclaimed, her hands playing with her own nipples.

Hearing himself be compared with a porn star made James feel strangely happy, his chest swelling with pride. No, it was actually swelling! With each sultry, moaning moo rising from his throat, his tits bloated and jiggled as James felt their weight press down on his chest more and more. He kept tugging and pulling his nipples, milk spilling over his hands and down the expanding flesh, making it deliciously slick.

"Oh fuck, bro--haaanh! You're getting so big, it makes me jealous!" Lily moaned, switching back to swaying her hips back and forth, rubbing the teat between her buttcheeks deliciously, milk spilling down her ass crack. James could feel his teat sliding back and forth between his step-sister's tight buns, thick cream spurting out all the while. But his chest was commanding most of his attention: It had crossed palm-filling long ago and was now spilling over the sides of his rib cage.

"Oh god, I think I can... mmoomfffh!"

James was right. He could cram both of his nipples into his mouth and breastfeed himself. Digging his fingers into his soft underboob, he began sucking insistently on the fat, expanding nipples, sweet cream spilling into his mouth. The taste and of course the pleasure made James moan hotly, the sound muffled by his tits of course.

"Damn, bro--ngh! That looks so... mmmh, incredibly hot!" Lily squealed, going back to bouncing on James' by now emptied udder. His milk had not only soaked the sheets, but also bloated up Lily's belly so much she looked almost pregnant, if only a few months along. James meanwhile kept drinking from his tits, flicking his tongue over his thumb-sized nipples, barely able to endure the bliss racing through his body. Neither was his step-sister, it seemed.

"Oh fuck, James! Aanh! Your fucking teat is gonna make me CUM!" Lily screamed in bliss, throwing her head back, and suddenly, her pussy was gripping James' teat much tighter, twitching and massaging the massive appendage. The sudden stimulation made James' whole body spasm, his nipples popping out of his mouth. The jerky convulsions of his body made his tits bounce wildly, flinging around thin streams of milk. James mouth flew open, and a loud, keening "M-moo-MOOOO!" ripped out of his throat, making the windows rattle. Lily slid off of James' udder, flopping onto the bed next to him. Both were breathing hard from the exertion and the incredible orgasms that had just wracked their bodies, a mixture of milk and pussy juices gushing out of Lily's twat.