Knob Of Butter.

Interesting to note, perhaps, that the phrase 'knob of butter' wasn't coined until as late as 1973, when, in The Last Tango In Paris, Marlon Brando had a chivalrous moment and applied said dairy product as a lubricant, before 'knobing' Maria Schneider up the wrong 'un.
Of course, as an actor, he was just going through the motions of intercourse, or, er, not, as the case may be.

I feel it will be a crying shame when the government finally gets it's way and culls the English pub culture to extinction, as I fear that these little gems of knowledge will almost certainly die with it!