The only time I have ever used towels relating to sex is if I squirted or years ago when I used to not let guys cum in me.
My husband doesn’t like when I squirt. He also either cums inside me or I swallow every time. He never cums on me. Neither of us ever need a towel. It seems like so many people use them tho
Edit: I go pee after which pushes the cum out of me. It doesn’t ever leak out