It's not wrong exactly. "Balls" is a slang term for testicles. It's not a polite term to use in public, or in a business or formal situation. You also wouldn't want to use it in front of your elders. But in a casual situation among friends, you could use "balls" if you want to.
Tennis Balls
Balls - usually as a reference to testicles but could refer to soccer balls, rugby balls etc.
Bolas, but be careful because with 'balls' you may refer also to 'pelotas' or 'balones'.
ballls balls ballls balls this one is wrong
that's just wrong mate.
maybe you need moisturiser
somthings wrong
Hell no what is wrong with you
that sounds wrong
Because you're doing it wrong.
Then you've pushed in to hard!
yes