Wiktionary
Etymology 1 vb. (en-third-person singularball up) Etymology 2
vb. (context British NZ vulgar English) To do something badly. To ruin a job.
Usage examples of "balls up".
She'd gathered my balls up in her right hand, was massaging them, gently, ever so gently, her lips sucking on the skin of the underarm and I thought I'd go mad.
But he tugged me forward, wrapping my balls up against my cock with his left hand, and he continued the merciless slapping with the other.
The Sergeant was choosing his shot now, rolling two eighteen-pounder balls up and down a stretch of bare earth to judge which was the more perfect sphere.
Jake was quivering, so close to release that he could practically feel his come traveling from his balls up into his cock, then Tor's tongue was gone.
I licked it closely underneath, pushing the balls up a little with my tongue, stabbing at them with my tongue, then I licked under them to the flesh right behind them.
She'd gathered my balls up in her right hand, was massaging them, gently.
Though thirty years have elapsed since the time of which I am writing, and though I scarcely once touched the balls during that period, I can still manage to read with ease while keeping three balls up.
She drew the hand that was massaging his tight balls up to his erection long enough to squeeze it.
She tossed a couple of the balls up to the ceiling and caught them happily.