An informal way to call your friend or to exaggerate an achievement.
P1: Wassup boi, i just got a double nuke in codm today
P2:Good job mah boiiiiiiiiiiiii!
The word "Boi" is in use when someone does something stupid, hand is also extended pointed at the person that did it
Guy: i haite english but lave reading
Class: Boi, dumbass