During sex, natch. 
Assuming hetero pair.
No, Who’s on first.
Third base!
(probably a good time to figure out who’s on top…)
All I know is What’s on second.
Parrot: I don’t care, I gotta see this!
She always ends up on top because it is the only way she can get off. We sometimes start out with me on top or sideways because she likes the intimacy.
We’re just the opposite. We often start out that way, but she can’t come when she’s on top (well, very rarely), so after we’re really cookin’ she’ll roll me over on top of her until she finishes. Then we’ll either stay there, or I’ll roll her back, or we’ll move into some other position. We usually cover most of the real estate of the bed before we’re finished.
I voted for male, me on top. But I could have picked indulging in other ways just as easily.
I really don’t like it with the woman on top. It really doesn’t do it for me. I wish that weren’t the case.
Why?
Male; I’m pretty much always on top. My wife has a congenital issue with one of her hip sockets, and any other position is uncomfortable for her (even more so now that we’re firmly in middle-age). I wouldn’t mind some variety, but it’s not in the cards.