Body writing is a fetish, but not a common everyday one. Many that indulge in body writing look at writing on a woman’s body as sort of laying claim to her as their territory.
Not as permanent as a tattoo, but marking her nonetheless. I have someone that for years has been asking me to write his name and slut on my ass and send him the pic……As of yet I have turned him down. He likes to write on the girls he fucks. He said he likes to keep the face pristine though, and only writes on their body, not face. Usually with lipstick and eyeliner. Naughty words, like slut, whore, cunt, fuck toy, etc. It’s also called erotic humiliation, since the words used are usually what many would find derogatory.
I asked him why and he didn’t have much of an answer, other than he likes it and it turns him on. I guess that’s good enough. With many fetishes we don’t know why they turn us on, only that they do.
Many into body writing also do like to record their “work” on film and take pics of their handiwork. It’s certainly less permanent than a tattoo and no great commitment.
There are chocolate body paints that are used for this as well, not just lipstick and eyeliner are used. Only a die hard body writing lover would allow something like a marker to be used, as that would take weeks to wash/wear off and someone might see that you didn’t want to in the meantime.