Not my thing personally. But with subs I have done anal training with them. Key is go slow lots of lube and slowly increase length and girth. Don’t force too large too fast or you’ll have a soft tissue tear. Marathon not a sprint.
A really important thing that is not often mentioned—go in at an angle! If you try to go straight in you’ll find it’s actually not lined up with your anatomy. Point toward your front about 45 degrees so the wide part of the toy has the easiest time passing through.