It is the intention of this posting to rescue this thread and pull it back 'above the line.'back to the peaseable kingdom....where all may contribute. It is true folk and not just a joke.

"An old forfeits game. The players seat themselves in a circle and one, take a wand, points it at his neighbor repeating the rhyme with mock solemnity. The player pointed at then becomes the one who points, and so on round the circle. 'It is a game', remarks Chambers, ' in which the only art consists in keeping one's gravity while saying absurd things.' Those who laugh or smile must pay a forfeit. Sometimes, to increase the difficulty, the one pointed at is made to take a more active part, and the following dialogue takes place.

1. "Knock, knock! (Thumping the floor with stick.)
2. "Who's there?"
1. "Buff."
2. "What says Buff?"
1 Buff says Buff to you again."
and I say Buff to you again."
2. "Methinks Buff smiles."
1."Buff neither laughs nor smiles,
But looks in your face ,[or strokes his face]
With a comical grace
And delivers the staff to you-sir."

OED quotes Cotgrave's French=English dictionary (1611), 'Esclaffer, to buff, or burst out into a laughter."

SOURCE: Opie, Peter and Iona , editorsThe Oxford Dictionary of Nursery Rhymes, Clarendon Press, Oxford, 1955, p 105.

Sincerely,
Gargoyle

Also noted is a German version from Simrock's Deutche Kinderbuch (1848)