grow some balls

absence makes the heart grow fonder

One feels more love or affection for those one loves when parted from them.

balls of steel

Courage, audacity.

balls to the wall

With maximum effort or commitment.

bust one's balls

To work very hard; to put in a lot of effort.

Cobblers

[Cockney slang]balls or 'bollocks'

via cobblers' awls

drag one's balls across

To exert extreme, often aggressive, power or control over; dominate.

great balls of fire

Expressing great surprise.

grow a pair

To be brave; to show some courage, especially in a situation in which one has so far failed to do so.