Wear a fake moustache, meet her in a bar and role play. Safest way to do it. Just don't go to Craigslist or any place like that. Too risky.
post here on ep she will get lots of takers, use condoms, are you going to watch?
Sounds like a good role play. If she's really into the idea, you dress up like the stranger. At least that way if you do get caught by the police you won't get in trouble when you explain you're just role playing.
kimmygary is right. Go with people she knows. DO remind her to use protection anyway. She can stage a scene using a bar, some "hook up" site, the back page of an alternative paper, or just use an imagination. It sound like fun.