Cunt.
The United States Air Force flightcap resembles the labia when viewed from the top or turned on end and has been called the "C" cap or cunt cap for years. Flightcap has become code for cunt cap and is a more subtle way of calling a person (usually female) a cunt.
The opposite of a cool down. When you are at the end of class and the coach says you are going to cool down but in reality it is just 15 more minutes of torture