pee-pee protector
another name for a mattress protector that prevents the leakage of urine from reaching the mattress. A pee-pee protector is often crunchy when it is dry, and not as crunchy when it is wet.
Guy: ugh, my pee-pee protector is soaked. I need a clean one.

Girl: Why is it soaked?
Guy: Because I peed.