When I was 15, I placed a folded towel on my bed one night, lay face down on it, and wet myself. Not a complete soaking, but enough for a huge wet patch to form on my light grey sweatpants. I wanted to see if there would be a visible stain on them after they dried out, so after wetting them, I stashed them under my bed, but threw the towel in the laundry.
The next morning I retrieved them and checked, but they hadn't even dried a bit. There was still a big wet pee circle clearly visible on the front. I stashed them under the bed again and went to school. When I got home, I went to my room, and went to check them again, but they were gone. Panicking a bit, I checked the laundry room, but no luck. I eventually found them washed and hanging on the line. Mum must've seen them under my bed and washed them.
I didn't know what to do or say, so I did nothing. She never mentioned finding my obviously wet pants, so it was never spoken about again.
I'd love to know what she thought though.