I don't get sleepy right after sex...I actually get invigorated. I want more! It's like while I'm getting fucked hard I zap all of the energy from my guy and it fills me and gives me more energy. Yes, probably endorphins...but I want more and more! The more awesome the sex...the more I want. I do sleep well after a night of hot sex, especially if my guy is NOT a snorer...But I would rather fuck than sleep!