There are as many ways to have sex as there are people in the world, which of course is incorrect, and I can back that statement up in no way whatsoever. I'd say maybe there are as many ways to have sex as there are Pokemon. That could be reasonable. So there's a lot, but not like an insane, unbelievable amount. That said, for all the ways there are to have sex, there's an equal number of ways to ruin that sex, intentionally or otherwise; blunders that just make the whole situation a wash. Rarely do you ever legitimately want to give up on sex when it starts, but sometimes you must.