It's probably genital violet and the person is trolling.
https://www.reddit.com/r/transparenttranskid/comments/ozn6cr/how_to_get_rid_of_the_hassle_of_having_to_tell/
https://www.reddit.com/r/transparenttranskid/comments/ozn6cr/how_to_get_rid_of_the_hassle_of_having_to_tell/