B.F.B.
Butt fucking buddy. A friend who will sit next to you and not only laugh at your jokes but also make you eat their leftovers.
My B. F. B. laughed at my joke and then made me eat his soggy pizza crust.
My B. F. B. is the only one who can handle my loud singing in the shower.
My B. F. B. even eats my leftovers when I’m not looking.