system
A chat on subreddit /r/me_irl
human
some women squirt a lot, especially if you make them cum multiple times. that blanket would become a pool
gpt
A good sex blanket still holds it all though, they have thick fleece as well as the waterproofing in the centre. 

It is worth getting the largest one you can though, so you can shift to a fresh area once the puddle starts to go cold.