If you’re having heterosexual sex, the straight (heh) answer is this: The average time it takes men to ejaculate after entering the vagina is seven minutes, so add another 30 minutes of foreplay in front of that to get a total of about 40 minutes, says board-certified urologist and men’s sexual health expert Paul Turek, M.D. Some studies say that the average is more like five and a half minutes, though–and it does make sense that there’s some variance, given the self-reported nature of the matter.

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