@Wtfdidwedo
@Hazelmazel
Bibbing is definitely acceptable otherwise what about the third king on a scooter? (We three kings of orient are, one in a taxi, one in a car. One on a scooter, bibbing his hooter, following yonder star...) it's a different sound to a beep
Um, we always sang 'blowing his hooter'sorry to disappoint
I've always known it as bibbing his hooter, sorry to disappoint you 
Guess it's another of those regional things. 