My little sister has gotten into a bad habit recently. Apparently she had just discovered from one of her friends that a guy's testicles are very sensitive, and she felt the need to test this. So a couple of weeks ago when I was in the shower she snuck in behind me and grabbed my balls, then started squeezing and pulling with all her might. It was hot in the shower and my balls were very loose, so needless to say it was very painful. And I'm not the big macho type that can handle these kinds of things.

I tried to grab at her and get her off, but she was crouched down too far behind me to reach. Her hands wouldn't budge from my balls either, no matter how hard I tried to pry her off. After about 30 seconds of me yelling at her to stop, threatening her in all kinds of ways, I felt nauseous. My knees buckled and I fell to the shower floor. While still holding on, she started shouting crap about how strong guys' balls are; so weak and vulnerable. Eventually she stopped and ran away, while I lied on the floor for another 15 minutes.

That night I tried to have a talk with her, and tell her that you can't do something like that. She's only 12, after all, and probably doesn't know any better. But the talk was absolutely pointless, she just played dumb the whole time, denying that anything happened. I got so frustrated that I walked out, but I couldn't bare to tell my parents about it. That's just too embarrassing for me to handle.

So for the last 2 weeks whenever it was just the two of us in the house she would sneak up behind me and try to grab my balls. Of course it was harder for her since I had clothes on unlike the time in the shower, but she somehow always managed to slide her hands up my shorts and squeeze just before I could turn around.

It's getting very dangerous now. Yesterday was the reason I decided to share my story here. She got a fierce grip on my left nut and I fell to my knees. She must have gotten good at it, as I had never felt this much pain before. I started getting woozy and losing focus, barely able to say anything to her. I passed out within 10 seconds.

I think this is what she wanted. I woke up in the middle of the den where I collapsed, completely nude, and sprawled out on my back. My balls ached like never before, and I'm pretty sure they were a shade of purple. I couldn't get up. My head was ringing, but I was able to make out the voices of two or three of her friends from school in her room.

I'm very worried that she doesn't know the real harm in what she is doing. I could've been neutered for all she knew. I can't leave my room without getting paranoid and constantly looking over my shoulder. I don't even shower or change my clothes anymore. Anything to avoid being naked around her. How do I get her to stop? I don't want to hit my sister, but that may be the only option. Help me!