Caught

Jack was about to masturbate one night when he heard a noise outside his window. He looked out and saw nothing. By then, his erection had gone, so he pulled up some porn on the internet. Then he heard another noise outside his window again. He looked outside and still saw nothing. He started masturbating for a while until he again heard the noise.  By this time, he just shrugged it off and continued.  When he finished, he checked outside again and saw nothing.  He went to sleep.

The next morning, his mom said, "So I heard you were masturbating."
"What?"
"Your father saw you from outside your window."
"Ummm well... He wasn't there, I checked!"
His father walked in and said, "Yeah, you checked the wrong window."