To be faunched is to experience the sensation of mild discomfort, annoyance, and disgust that one commonly feels when a large and determined dog is sniffing one's perineum, or taint. This particular combination of feelings is commonly experienced in social settings, with unpleasant or needy attention from another person.
"That creeper at the bar last night faunch
ed all over Gwen- I hope she didn't get drunk enough to go home with him."
Faunch: verb, meaning to rage and storm, to fight against fate. "Faunching at the bit" implies waiting in nervous agitation and impatience, like a wild horse that is fighting against a harness. Probably derives from Irish "fonn taodach" - to quote Daniel Cassidy's book, "How the Irish Invented Slang" (p.139) "an impulsive frame of mind, jittery excitation, a fierce humor", taodach meaning "excited, fidgety, quick-tempered." (Cassidy's entry was not defining "faunch", but "fantod." I made the leap myself.
I was faunching at the bit to drive my uncle's new Mustang.