in cold weather it is the ultimate description of pain
Person 2 "yeah John's arse was so red....."
The heat of the funnel generally burns their arse! Thus new guys get a day or two leeway when they join a ship and are forgiven for sitting by the funnel! A senior rating (sailor) will refer to a junior "STFU you're nothing but a red arse" basically I've been around this ship longer than you!