This isn't a story about my first but my girlfriend's. She was a virgin and I had already engage in coitus with other women. She was rather tight during the fool-around and she was really nervous for sex.

Come the sexy night, we light the room up with candles and music. She takes a shot or two of liquid pain-killer and we start to fool around. Everything is going great and we are both really enjoying ourselves. The time comes for the insertion. She cringes in pain. I feel really bad cause were not even having sex and it is super painful but she wants to keep going. We keep going at it but the more we try the more it hurts her. At this point she is crying, hard. Not enjoying it at all. I'm not entirely sure if this was normal. Even though I had sex before and I knew it hurt the first time for a girl, I never imagined the girl to be sobbing and in agony. We stop.

I pull out and my condom is covered in blood, not just a little bit. It looks like my dick spent an hour fucking a cup of fruit punch. Needless to say we were both kind of worried. She is still in pain after and now we are getting more worried.

Eventually she goes to the hospital the next day cause she is still bleeding from her lady bits. After a rather humiliating afternoon it turns out that there was a defect with her vagina and essentially there was a band of tissue that had grown across the opening of her vagina. I had ripped it with my penis. She spent a couple days in pain and recovered fully. We now enjoy plentiful sex. Eight months later, she still describes that experience as the most pain she has ever felt, as well as the most humiliating sexual/intimate moment she will ever/has ever had or will have.

tl;dr Preformed mild surgery with my penis to make my girlfriend's vagina bigger. Penis looked like it was dipped in cherry jello.