Girls, looking for your help on this?

sorry this is so random. i'm 13 and my 14 y.o. brother punched me HARD in the boob today. it's not the first time he's done it, and in the past my mom's grounded him and stuff like that. this time, though, she said she would take away his iPod for one day OR i could hit him in the balls. it's my choice. my sister said i should go for the balls, but i don't know what shoes to wear or how to position him for it (i don't have to do a sneak attack, he's gotta just take it - standing up, kneeling, etc.). so what are ur ideas? help me out, girls!!!