There are a lot of other options that don't refer to specific body parts, but I gather that you want something similarly vulgar but referring to female anatomy. It's not all that common, but if you said something like:
"Get off my tits!"
the meaning would be readily understood.
(Note: the expression "off my tits" or "off her tits" can mean other things, like very drunk. "Get off ..." is distinct enough that there shouldn't be any misunderstanding.)
That being said, in the appropriate situation, a woman using "Stop breaking my balls!", (in the appropriate situation)"Stop breaking my balls!" is both completely acceptable and pretty funny. In the right context it can be the perfect comeback.