As long as it takes. It depends on the position, the guy, and the duration and type of foreplay. Sometimes I can have an orgasm in a couple of minutes, but often it takes longer. If I'm allowed to get him aroused orally, I'm usually pretty wet before he ever pokes it into my vagina. The risk I take is he cums in my mouth or on my face before I can put him inside me. But that has it's own rewards.