I once dated a guy with klippel trenaunay webber syndrome, due to the syndrome he had to have his right leg and a testicle amputated as a baby. Also because of it, his remaining testicle was enlarged, about the size of a melon, covering his penis to the point that only an inch was exposed when erect. On top of that, due to the disease and he fact that he was extreme unhygienic, his teeth were yellow/brown spotted, his hair was greasy, and he smelled of blood all the time due to not washing every day. That wasn't even what made the sex bad, he wasn't willing to give as much as he wanted to receive. Pretty much like fucking a sac of potatoes and even then, you can at least eat the potatoes afterwards.
And that's how I lost my virginity and 5 years of my life. The decisions you make relationship wise when you're still in high school...
Normally I'd sound like a total jerk for mentioning all of that, but he had the worst personality, the biggest jerk I've ever met, not to mention spineless. Let's just say that after we broke up (still very much friends at the time) I was in a life or death situation, he was the only person I could get in contact with and he hung up because he didn't want to wake up his roommate by coming to get me.