I made a short review (it should take less than 10 minutes to read it) about one of the dual density dildo from Hismith.
The sextoy is made from a safe material which is silicone. You can fully sanitize it without difficulties. Also, the shape of the dildo make it safe to be used anally. There is no risk to have it stuck inside you during use.
This sextoy, as I said previously, have a dual density. There is a first layer in firm silicon and a second layer of a softer silicon having a phallus shape (with balls).
It's quite flexible to don't hurt if you're not used to play with dildo anally, but also firm enough with the inner layer in order to have it stand up.
More insight on this sextoy in my review https://foxypleasurereviews.com/hsa20-gc-en/