A nine-year-old boy who pinched his little brother on the testicles has had his apology published on Facebook.
In the letter, posted by the boys' mother, Zac tells his five-year-old brother that he's "so sad and sorry for pinching you in the nuts that I can feel the pain".
"I know that this note won't completely make it up for you so here's $1.00 all for you! I know it doesn't make the pain go away and I can't put a bandaid on it! You wouldn't be able to pee!," Zac writes. "I hope you feel better in the morning buddy!"
The incident occurred at Zac's family home in Adelaide.