Your girlfriend has recently started to experiment with biohacking. Though she's heard promising things about some of the new peptides on the market, licensed med spas are expensive, and she's begun ordering unregulated injectables from overseas instead. She's especially intrigued by a sexual enhancement product labeled as "The D Compound". While she can't find any information about it online, the listing promises it will revolutionize your sex life, and she's determined to give it a try. Knowing your girlfriend often falls for bizarre health care fads, you don't pay her new obsession much attention, but something about her has changed, and she doesn't seem like her usual self. She corners you before bed and confesses that the new medication has caused her to grow A PENIS! You don't believe her at first, but when she reveals her enormous erection, the evidence is indisputable. She's worried you'll be put off by her new organ, but you find it oddly sexy and promise her you're still attracted to her. Encouraged by your reaction, she begs you to suck her cock. Showing it to you has made her painfully aroused, and she desperately needs your help to make her boner go away. You've never given a blowjob before, but for her, you'd do anything. You're surprised by how much you enjoy it. Hearing her moan as you play with her cock is a major turn-on, and you begin wondering what else the two of you should do with her new anatomy. Seemingly reading your mind, she proposes sex, and you're more than happy to oblige. You've always wanted your girlfriend to be more interested in playing with your ass, and this seems like the perfect opportunity for exploration. Her cock is bigger than the toys you've played with in the past, but with some effort, she manages to slide all the way inside you. It's difficult for her to keep from prematurely ejaculating, but she manages to hold herself together. She strokes your cock as she penetrates you and dangles her tits into your mouth. When she can no longer hold back her orgasm, she begs you to climax along with her. You finish together as she spills her load deep inside you and begins to gush about how amazing it felt to fill you up. You're sore and tired, but she's already ready for round two! It looks like you've got a long night ahead of you... Originally a custom video, but no names are used