washable mat for naked time for baby

is there something that you could use for diaper free time with baby, then throw in the wash if they pee on it?

we have been using leftover chucks pads from our home birth, but are running out. but also they bunch up when she moves her feet and arms so they're not ideal anyways.

we do cloth diapers so my thought was maybe something made with the PUL material similar to wet bags. but i'm not sure if it exists or how i would get it to not slide around. what do you all use? we have carpet so i need a waterproof layer.