What is Fill-in Friend?
1.
A person who is a friend, only when your other friends are not present.
Also referred to as a "number two". Any social networking site has a Top Friends, and the number is your next best friend.
"Well, John isn't here, so I guess I'll have to talk to my fill-in friend."
"Amy had to go to the concert, so I guess it's just me and the number two."
See
