I think he just can't hardly believe his drawer is full of clean laundry every day and thinks he's gotta use it up!
I've asked him about it...said "Who wears 5 pairs of underwear in a 24 hour period??" He just thought that was hysterical and laughed...but never answered me!
Sounds like the work of Underpants Gnomes to me. . .but I can't find a good picture of the Underpants Gnomes, so this is probably the next closest thing: