"Yes Sis, your boyfriend kicked me in the balls because he doesn't want me to look at your tits. Do you want to kick me in the balls while I look at your tits again? And please don't tell your boyfriend."
"I'm so glad you want to dominate me. My balls are going to hurt, I know that, but I'll happily get on my knees with my legs apart so you can kick me in the balls."