Ok, I wanna ask this. I'll try to keep it as adult as I can. Why is it that after most males have an orgasm, that they are very tired and find it easy to sleep afterwords? This is true for me. From what I think I've read, the sympathetic nervous system is "active" during the build-up to orgasm, and the parasympathetic nervous system is activated at or directly after orgasm. Since the parasympathetic nervous system slows down the heart beat, makes you relax, sends blood elsewhere, etc, is it the activation of the p.s. nervous sytem that makes you "tired" after orgasm? Or am I totally off base here?