Try the shorts on for size

It occurs to you that this would be pretty hard to explain it anyone else came along so you gather up the parts you've found and the rest of the basket and retreat to the relative privacy of your room.

Shutting the door you spread the basket's contents out the bed and returned to examining the shorts. They facinate you, despite the fact they technically were your mother. The skin fabric is so soft and warm to the touch. A shiver runs through you, an illicit thrill of excitement at man handling her most intimate parts.

As you run your fingers around the waistband an even more perverse thought crosses your mind, what if you wore them?

Setting aside any pesky moral qualms you strip down and pull them on.