English Cockney Rhyming slang: cobbler's awls - balls. Awls in this case being tools used by cobblers (shoe-makers).
It was a right load of cobblers!
Short form of testicles. You may also know them as balls, bollocks, cojones, huevos or nuts.
I use all of these terms, and more besides, but then I am Ian Chode, the greatest swearer of modern times!
Chode: Eat my testes, bitch.
Bitch: OK. Mmmmm, better than McDonalds.