Very drunk. Etymology: the recently-revived 1980s fruit drink Um Bongo.
("Way down deep
in the middle of the Congo,
A hippo took an apricot, a guava and a mango.
He stuck it with the others and he danced a dainty tango.
The rhino said, "I know, we'll call it Um Bongo"
Um Bongo, Um Bongo, They drink it in the Congo.
The python picked the passion fruit, the marmoset the mandarin.
The parrot painted packets that the whole caboodle landed in.
So when it comes to sun and fun and goodness
in the jungle,
They all prefer the sunny funny one they call Um Bongo!" TV advert probably pulled owing to minimal likelihood of the Congolese actually shipping in long-life
tropical fruit drinks from the UK.)