Morris seems to have somehow burned the seat of his pants off, perhaps he bent over too close to a burner on the stove, or it's the aftermath of his little slip-and-fall that got his rump stuck in the oven ( http://lorddominic.deviantart.com/art/Rump-Roast-419493193 ). He seems very embarrassed to now be showing off his boxers, which feature a doughnut print today.

It could be worse, Morris, you could be showing off your buns!

Being a cook, I like giving him boxers with cute baked goods prints (cupcakes, doughnuts, pies, etc.) with a pastel color background.
Maybe he should start keeping spare clothes in the kitchen, he seems very prone to this sort of mishap.