Sabrina’s boyfriend had one of the engineered cocks that were all the rage. His new cock was thicker than his own wrist and was designed to never get soft.

No matter how long he fucked her ass, no matter how many times he came, his cock would always be rock solid, thanks to a carefully designed cartilage structure which took the place of the corpus cavernosum.

It had been a little slow to catch on, but once men realized that they could get a lab grown penis of any size, that was always hard, and that (thanks to sense boosting technology) even felt better than the original for them, nearly every man had opted for the surgery. It had become so commonplace, that prices had dropped, enhancements were offered at many clinics, and cock-design was the business everyone was training for in college.

Sabrina knew her boyfriend would be fucking her aching asshole for at least four hours that night, cumming at random times, thrusting the entire length so far up her ass she’d feel like passing out.

He told her he’d be getting an even longer and thicker cock the next month. She wondered if she’d even be able to keep from passing out after a few thrusts when he got his next upgrade. Despite her doubts, she thanked him and promised to start training her asshole for his new tool right away.

(PS - Lab grown penises on humans are soon to be a real thing. While the engineered, ever-hard, cosmetic penis might be a little ways off, I bet it’ll happen sooner than people expect.)