One of my favorite ways to masturbate is to wet my panties and then start touching myself through the wetness. I usually end up putting my hands inside to finish, though.
One night several years ago I was talking online with a younger female friend who hadn't yet come to a conclusion about whether she was gay, straight, or bi. She'd had a long affair with her college roommate but was then with a guy. She revealed that she and her roommate enjoyed peeing together and watching each other, and even watched each other wet their panties, which apparently triggered an evening of wild sex. Then she said one time they wet their panties together and then traded panties. Now I am about as straight as it gets but that really got me hot and I started to wonder what it would feel like to do that. I wanted to ask her about it but didn't. Later on that evening I was still thinking about it and I went outside on my patio and wet my panties, then came in and stripped down to just the wet panties and started masturbating through them. I was so hot thinking about masturbating in someone else's wet panties that I came without putting my hands inside. I still fantasize about that from time to time.