The process of befriending the best friend(s) of your best friend. Given the mutual common best friend, a relationship can easily be formed with your best friend's said best friend(s).
My best friend's friends came to visit this weekend. I instantly became best friends with them through the process of Osmosis Besties. We are now one group of real life Besties.
by KyFace September 28, 2009
Get the osmosis besties mug.