The word mbubu refers only to this ceremonial gourd mask. It is worn during a secret initiation ceremony known as bkpe in the southern Afikpo villages, Kpogrikpo and Anohia. The Nkporo Ada wear similar calabash masks, with vertical fibre extensions, during ceremonies and it is said that some Afikpo rites are based on these traditions.
During initiations of eldest sons into secret Afikpo societies, novice members wear the mbubu mask (called isiji among most other Afikpo villages; meaning 'head of yam').
These masks can be worn by hundreds of male members of the groups ranging in age from five to around twenty.
Mbubu masks are said to be more powerful than other Afikpo headwear and are rarely touched other than to carve duplicates or perform initiations.