I’d prefer it if one character were human , but it’s not necessary; I’d be interested in some shifter-on-shifter action! ;)
If you are interested, I do knew of one book that somewhat fits the bill. It’s an FMM fantasy erotic romance series by A. H. Lee that begins with Incubus Caged. The incubus is a panther shifter. There’s only some oral while he’s in his panther form, no intercourse.
Source: reddit.com/r/Erotica/comments/gdaeu7/looking_for_werewolf_or_other_shifter_erotica_in
I can write a few and know where you can find some
Amazon has a ‘monsters of lust’ mini series. One is a werewolf and one is a tentacle thing. I don’t remember what the first one was about though.
Check out Kelly Lord on Inkitt. She writes really good shifting erotica!
The Anita Blake series from Laurell K. Hamilton. https://en.m.wikipedia.org/wiki/Anita_Blake:_Vampire_Hunter