Thor and Odin are up in Valhalla and Thor turns to Odin and says, "It's great being a god and everything but I haven't had sex in a millennium." Odin says, "Well, what you need to do is go down to earth and find what they call a lady of the night and treat her." So Thor goes down to earth and the next day returns with a smile from ear to ear.
Odin says, "It was good, then?" "Good?" replies Thor. "It was great! We did it twenty-seven times in one night." Odin is horrified. "Twenty-seven times?!? Mere mortals can't handle that! Go back to earth and apologise," he tells Thor.
So Thor goes back and finds the woman and says, "Sorry about last night, see, I'm Thor..." The woman replies, "YOU'RE Thor? I can't even pith!"