Plane Friend 

When you don't want to, can't, or it wouldn't be prudent to claim to have only one best friend. You have plane friends. They are best friends that you would jump on a plane for if they said they needed you.

Choose your plane friends carefully because they would also have to be willing to do the same for you. Generally, you don't have these until you are an adult and all your friends are scattered throughout the country.

I don't see Marc that much, but his still one of my plane friends.

Plane Friend by CalliopeDM April 12, 2010

Third place friend 

When you or another person is always third place when there is a friend ranking.

Hey! You are my third place friend! Right after Sheila and Kobe!

Third place friend by Pop13 May 4, 2023

time and place friend

A time and place friend is a friend that exists only within a specific time frame and at a specific place, and in any other scenario that friendship would not have formed. Usually in the context of traveling abroad or being in a novel situation.

Charlotte and Bob, who were as different as night and day, met in Tokyo by happenstance and became time and place friends.

time and place friend by phrmashwrma November 25, 2023

Friends & Family Plan

When your sister/brother in law is not being sexually satisfied by their spouse or significant other and want to hook up with you and keep it undercover & within the family.

John: My sister in law told me she is starving for some dick. Said Bill doesn’t do it for her anymore.

Joe: Sounds like she is trying to get on the friends & family plan with you.

Friends & Family Plan by The Fratriarch October 10, 2023