Fake cocktail/drink. The word exists purely as a way of cracking
a joke at a barperson's expense whilst your
mates are standing round, thus guaranteeing you kudos
for the rest of the evening.
For best effect, order a few normal drinks, then finish off by requesting a matabooboo.
The word originates from
Yogi Bear's sidekick. See example for full usage and relevance details.