Exchanging a pair of BFF bracelets is indicative of a powerful bond. You don't do this with just any old Tom, Dick or Harry in the cafeteria. You do it with the person who is your most loyal friend and trusted sleepover partner, someone you'd totally trust with your locker combination if you had to.
For Vice President Joe Biden, that person is President Barack Obama.
He formally declared as much on Thursday via a tweeted image of Joe-Barack BFF bracelets, in which he wrote out the phrase "best friend forever," so as to make the meaning of the BFF bracelets perfectly clear.
Will the BFFs be celebrating Obama's birthday with a pillow fight and hair-braiding sesh in the slumber-party wing of the White House this weekend? Yes, probably!