I never have and like to think I never will. In fact, outside of porno movies I know of only one case. A girl at high school stopped attending and I asked her friend why and she said because she was pregnant. She went on to tell me she got that way by sleeping with two guys, one after the other, neither of whom wore a condom. Also, if you are hetro and have done sloppy seconds, didn't the other dude's juice make you hesitate? I can understand how it would be less gross to a gay dude, just as pussy lub is not disgusting to a hetro guy but probably is to a gay guy, but surely it must have made you think twice.