my b/f's ex-g/f tried this, but it didn't work. after he came she asked him if she could take the condom off him. he said yeah, sure. she took it off him and then laid back on the bed holding it up looking at it for a second. then in one swoop, she put it down there and turned it inside out - unloading it inside her.
she had been trying to pin him down for some time - she really wanted to have his baby, but he wouldn't go along with it. he never thought she'd do something as stupid as that though. the condom was not a spermicide condom, and like i said, it did not work (not to say that it couldn't though).
some people are just sick in the head. my b/f made sure she wasn't pregnant (basically stuck around until the next time she had her period) and then broke things off with her because she was a freakin' psycho.
i hope that's not what the original poster was planning on doing. it's sick, and ppl who do that need help.
jasmine