With the majority of society believing that it’s socially acceptable to talk in public about redheads’ nether regions, you will likely be asked if you have a ‘fire crotch’ at least once in your life.
The nickname means that because you have ginger hair on your head, that you simply must have red hair down below and you simply must discuss it with them. Immediately.
The uncomplicated formula to this type of ginger nickname is:
“something orange-coloured” + “a reference to your nether regions” = “inappropriate redhead nickname”
See also: ‘fanta pants’