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He showed Homer to his room and assumed he would be sleeping with Mindy Simmons and makes various sound effects to emphasize sex. Homer tells him that he will be using the bed for sleeping, eating and maybe making a fort, but nothing else.
He is later seen with a floor buffer making a noise very similar to Marge's disapproving groan. He later comes into Homer's room when he and Marge are in bed and makes his noises again.