A large lump of uncertain origin located directly behind the ear. It causes the ear concerned to protrude at 90 degrees to the head. It ranges in size from about the diameter of a golf ball to that of a small melon.
There are varying theories as to the cause of this phenomenon, the most popular being that it is caused by partially digested fragments of swiss roll that take up residency behind the ear when there is no space for them in the belly.
The bokbagasie can be surgically removed, but this is not often done because of the extremely high rate of re-occurence. some bokbagasies have been known to re-occur as little as three hours after being removed.
"My word, how radiant your bokbagasie is looking today"