Genie... So poor he didn't have a pot to piss in was in use on our side of the Atlantic too, my old Gran used to say it.
Also, of someone nervous, ' He's jumping about like a fart in a bottle!'which is fairly close to your version.
This next is not exactly a family saying, but a tale often told. Dad was at a wedding, and trying, as only an awkward adult can, to make conversation with a small boy:-
Dad... And what is your name, young man?
Small Boy..... They call me Waspberry Arse!

There is really nowhere to go after an exchange like that!

FC