Personally, If I were to shave a bun’s privates I’d feel uncomfortable even after having a vet teaching me how to. My bun was especially squirmy!

What I was comfortable with, the times he needed to be extra clean around his butt, was to keep the area clean by washing/drying it, cutting matted hair with a tiny pair of scissors and treating the inflamed areas with a specific ointment prescribed by the vet (it was a neem oil based product).

I’m sure more experienced members can be more helpful, sorry!

I know one of our members (no longer active on the forums) just recently gave her bun a sanitary shave with they type of cutter we normally use for our own bikini shaves 😀 She took great care to not go too close to the skin because you don’t want to nick the skin, obviously. It helps a lot f you can get someone else to help you hold the bun.

Once you get the mats off, weekly maintenance could perhaps be managed with cornstarch baths? I did cornstarch baths for my bun Bam who was prone to poopy butt and had tangly fur. Basically you massage cornstarch or potato starch into the soiled fur, pick out lumps that form, then brush.

Even if it were a common practice, it’s not good to do anything you don’t feel comfortable with, because you’ll be nervous and they can feel it! (unless it’s something life-saving like admininstering medicines, for example… that has to be done…)
I’d say call the vet and ask about an ointment or something to soothe the skin and do try the dry or cloth butt-baths? maybe in the meanwhile try another kind of litter material that’s more absorbant and change it more frequently?

I agree that I would prob wait for the vet to show you, especially since your bun is hard to handle. A bum bath or a cornstarch bath would be a much safer approach. Usually ongoing sanitary shaves are only done on buns that are incontinent due to illness or injury. Fixing her litter box set-up is more important that the shave.