friends shelf 

Usually pertaining to guys, the friends shelf is when a girl labels you a friend, disallowing you to be anything more then "just friends".

I am on the friends shelf because this girl hangs out with me and we get along great but i will never be more then a friend to her.

friends shelf by Tongnar July 11, 2006

shelf friend 

When you become an option. You are not first pick of friends. When your friend starts dating someone and you are put up on a shelf until they have no other people to hang with.

I don't need you anymore, I'm dating somebody. So I'll put you up on the shelf until I have a need for you. You are my shelf friend.

shelf friend by Pix_n_stones July 16, 2017

self-serving friend

An individual who is only your friend to use you for their own personal gain and is magically not around when you actually need a friend. Also known as selfish and a bitch.

Wow, you know Jessica, we should have seen right through Rebecca, she is such a self-serving friend; she only wanted to be friends with us so she could pass bio lab.

self-serving friend by Good Friends United January 15, 2009

Self Esteem Friend 

Abbreviated as "SEF"

The friend(s) of a highly attractive girl who's sole purpose is to make the attractive girl feel better about themselves and look perpetually times more attractive to guys.
Also, the SEF serves a double purpose as a cockblocker

Charlie: Yo check out that slut over at that table, shes hot as fuck. Im'a go get that.

Justin: Yeah dude, but check out all her friends.

Charlie: Fucking Self Esteem Friends...

Self Esteem Friend by You Wont, No Balls June 9, 2011