I also had that happen but in a different way. My girl was riding me cowboy, and just as she was climaxing, she leaned back and came down real hard. My penis went in her anterior fornix, bottomed out and bent. I fealt a pop but it did'nt hurt. When I pulled out, I could see blood dripping from her. I asked her if she was on her period and she said no. When I went to the bathroom to clean up, I ended up squeezing blood out of my penis. I went to the hospital the next day and had to explain what had happened to the nurse (embarassing). All tests showed no serious injury so it must have been a small rupture. Lucky, but still scary as hell.