Sentence:  At Rick's side our local Liberal Party Chairman is smacking his yeoman's paws together and <WSD>rhubarbing</WSD> ecstatically in Rick's ear. 
Meaning of the word marked with <WSD> tags:  Of an actor in a film, stage play, etc.: to repeat the word "rhubarb" to create the sound of indistinct conversation; "hence", to converse indistinctly, to mumble.