I can't say I've ever turned it down for another activity.. Generally I'll only turn it down when I'm not, or no longer, interested in having sex with a particular woman.
I like to break sex down into three catagories: Lovemaking, General Sex, and F{bleep}ing. A completely spiritual and intimate moment, regular sex but still caring about the other person, and throw down - we're only here cuz we need to get-off... Respectively.
Each has it's merit and purpose, and I believe each should be tried by everyone at least one time before even considering settling down.
But that's just me.
