Your best friend's, best friend. This might be your BFF's, best friend from High School, the city they grew up in, or their new best friend from whereever they have now moved to. Since this new person is your BFF's, BFF they have already been screened for trustworthiness and loyalty and of course they have the same sense of humor as you! So when you meet this person you instantly love with them. Hence, they become your insta-BFF.
I went to Florida to visit my best friend from college. One of her best friends from High School joined us there. Her best friend and I hit it off so quickly we must be insta-BFF's!
by hurdlingpride March 26, 2009