902jon,
Bit of a urban myth nowadays. Check ins are always:
"skin"
"2"
"3"
"skin 4"
"Benson App, Skin, 4 merlin....."
Worse still is the use of "Skin formation" mil call signs are there to indicate that you are a formation......just the call sign should be used.
Not good when ATC controllers mishear "Demon" for "Seaman"......worse still when they ask "does your call sign have two a's in it or two e's" ;-)