How to know the sex of my turtle?

how do I know if my turtles a boy or girl?

well I think it might be different with different types of turtles, but if you have the common red-eared slider I read in a book once that if the tail is 'long' and thin it is a girl and if it is short and stumpy it is a boy.

how does that fit in this cat. I had a friend who called his d*ck his trutle but you should know weather its a male or a female
or do you love your turtle maybe your some freak who wants to 'go all the way with his turtle'
just kidding but if you do make sure its not a snapping turtle

I don,t know but I would like to know as I have a baby snapping turtle I,ve had since last september .so if you find out let us know. thanks.