A person in your friend group that you secretly hookup with. You sneak out (usually at night) and do anything from talking, cuddling, making out... to sex (but not always sex). They respect that you want just a hookup friend and you respect them as well. This is not a closed relationship and you expect eachother to hookup with other people- but only if they are not in ur immediate friendgroup. People often use this method as a way to get around ever having to be commited in relationships while still getting some action.