In my experience, one night stands are pretty much all night fuckathons. Pretty much every/any inventive position is used after we see how well they work anatomically. Typically with a new partner, I start off with her riding me, so we can see how much penetration is OK without hurting, and then we take it from there. As per anal, I've never had anyone let me do that on the first date, and the vast majority of the women who I've slept with never wanted me to do it.