Supermistaken
Superman was feeling bored after a long break of crime fighting and wanted to go out and party. So he called Batman to ask if he wanted to go to a club and pick up some girls. Batman said Robin was ill and he had to look after him.
A little disappointed, Superman called Spiderman to see if he fancied a few beers. Spiderman told him he had a date with Catwoman.
As a last resort, Superman flew over to Wonderwoman's apartment to see if she was free. As he landed on her balcony, he saw Wonderwoman naked on the bed with her legs open. Superman thought to himself "I'm faster than a speeding bullet, I could be in there, have sex and out again before she knew what was happening."
So Superman did his super thing in a split second and flies off happily. Meanwhile on the bed, Wonderwoman said "Did you hear anything?"
"NO"! said the Invisible Man, "But my ass hurts like hell!"