Urethral penetration, but one of the cocks is actually someone who has been transformed into someone else's cock.

Willing, consensual bad end stuff? Snuff, vore (cooking especially?), permanent transformations? Maybe someone gifting their butchered body and meat to a friend for their birthday? That's always cute. <3

Hmm, how about getting injected up the cock and getting huge bladder inflation?~

More urethal stuff! :D
Ball inflation, urethal penetration, tentacles, lots of cum, you name it!

Using intestines as rope in various scenarios. Paticularly as a noose or for bondage

dick biting
I might commission this from you anyways

Maybe something new with that character https://www.furaffinity.net/view/11176177/ ? As reminder, he is a kirin with ability - everything that touch his sperm transform into sperm too, as chain reaction. I have some old ideas for him, but could I use notes instead of the journal?

some slime assimilation stuff or absorption?

Wait a second, "suit Brain play"? This sounds like something i could to - mind pointing if there are some drawings about that?