Yes, a man transforming to a woman and having sex with his friends is a fairly common trope in hentai. 4chan started off as a clone of a Japanese website and is fairly weeby to this day.

Creative writing involves, at least to me, letting your thoughts arrange themselves in freeform fashion without constraints. Anything written can be trimmed but thoughts should be able to explore themselves using you as a medium. Just be malleable and unafraid of what you find and you too can project confusing experiences onto others! As an aside, chatgpt is terrifyingly good at writing true greentexts.