In Plum Sauce, (A P. G. Wodehouse Companion), author Richard Usborne deals at some length with characters who "buzz" or agitate the conversation in order to "start something." For instance, he notes that Psmith does it frequently merely because he is bored and wants entertainment.
To the surprise of no one, however, his champion "buzzer" is to be found in one certain cheerful gentleman who appears mainly in the Blandings Castle stories. "Take a line through Psmith and fifty young heroes and heroines of stories and novels, and you fetch up at the biggest of all the irrepressible buzzers, Lord Ickenham. His talk is like the flail of a tank going through a minefield."
More HERE about the Uncle Fred and the dog races.