I tried sounding a few times years ago with a new tiny slim thermometer. It felt nice actually. I made sure to pee prior and then drank some cranberry juice. it only went in a inch but..then i used my vibe on the outside and amazing!!!!  Catheters i've never tried but i'm curious about them. i've seen videos of catheters being used as like a fetish..and it is arousing to watch. 🙂