TL;DR at bottom!

Hey, if anyone has any experiences as a partner, themselves, or friends / family, or toy recommendations.

(Being brief) I've had an anal fistula for at least 4 years. It's extremely close to my anus, and it's "below" the anus, meaning normal #2 in a toilet never really affects it, but say lube leaking out laying down, would certainly potentially get inside and cause issues. Completely dormant and 0 issues. (being brief here, yes I know there is surgery etc etc)

I'm wanting so bad to try anal masturbation, especially plugs. When I masturbate normally I "feel" my anus and desire stimulation. But because of the fistula I'm afraid to try penetration for fear of something leaking into it or making things worse.

SO does anyone have toy recommendations for like a vibrator or something I could just push up against the outside of the anus or even lay / sit on? I'm a guy so it would be nice if it could like stay in place somehow...My thought is atleast I could add pressure or vibration on the outside and keep everything clean and tidy to prevent any issues from creeping up.

TL;DR: Any recommendations of toys or techniques to stimulate the outside of the anus without penetration. I'm a guy, so something that could be somehow held in place would be amazing...