Yes

You make a fist with a right hand and hit yourself in the balls.

Rose smiles. “Was that it? I know you can do better, just do it like I’d do it, show your balls no mercy. There’s no point having that punchbag under your penis if you don’t use it.” She moves her hands to her hips and hooks her thumbs into the sides of her panties, jiggling them about. “I want you to keep hitting those balls of yours, and if I think you’re holding back or hesitating then you’re not seeing anything. Deal?”