Help with a trans man sex scene

Story by Gydian

I'm writing a story, that may end up being as long as a book. I have a scene where the main character has invited a trans man to have sex with him and his girlfriend. I'm a heterosexual sis male, so I have absolutely know experience with trans men especially naked trans men. I would like to write the scene accurately as well as very sexily. Are there any people who can help with info or links that may help with this?