From memory of circa 55 years (in other words b***** unreliable) of my long-deceased Father's performance;

To the tune I think known as the "barber surgeon's knock" or "Postman's knock"

'Three jolly consumptives (or sometimes rendered as conservatives); *,*,*.'

*is an difficult-to-decribe, throat-clearing sound, in 3 stages.

To give Dad his due, this was a rarity, seldom 'performed'.