Ben Elton is a comic who gives a performance rather than just telling jokes. This phrase is from when he was talking about the British delight for queueing (and complaining about people pushing in) when getting onto a train, where everyone's desire is for a double seat (never sure if this means a pair of seats, or two pairs with a table between, but it doesn't matter).
He chants this phrase over and over, describing the queuer's impatience and obsession, and taking the audience with him, building up to a climax when the queuers finally get on board and put the 'bum on seat'.
It's an excellent example of 100% capturing the audience's attention when performing. Personally I'm not keen on much of Ben Elton's stuff - he tends to labour points too much (repeats himself a lot).