My girlfriend teaches her little horny sister to bust my balls

My girlfriend Sarah and I have been together for six years. I’d say our relationship is pretty good. However, sexually it could be a little more exciting. She’s more of a vanilla girl, so our sex life is only moderately exciting. Don’t get me wrong, her body is breathtaking, but I’m just into more rough stuff. I was open about my ballbusting fetish early on in our relationship. At first, she was a little put off, but over the years she’s become more and more willing to explore this fetish with me. Well, she does it because I like it, however she doesn’t really have any enthusiasm for it.

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I was at Sarahs family’s vacation house with her and her little sister Ashley who had just turned 19, which made her six years younger than us. I’d known her since she was a little girl, but she’d really matured a lot lately. Big breasts, athletic body, and a charming face... Yes, she was prettier than her older sister. I didn’t want to admit it, but I had a crush on my girlfriend’s little sister. Maybe it wasn't just about her looks but because she was more lively and mysterious.

So there we were, the three of us, lounging in our beach chairs on the patio, enjoying a warm summer night with a few drinks. Both girls were in their bikinis. I felt guilty because I couldn't take my eyes off Ashley. Her smooth, soft skin, her big butt, and her full breasts. She was just so beautiful.

As tends to happen, the conversation grew more and more interesting as the alcohol started to kick in. Sarah, in particular, was drinking quite a bit that night and was already drunk, while Ashley and I were still quite sober.

“How was your date with this Michael yesterday? You didn't mention it at all.” my girl Sarah asked.

Ashley replied, looking a little embarrassed, “Oh, right, it didn't go so well. Actually, he was a total jerk. I thought he was a nice guy, but...”

“But what? ... Tell us,” Sarah demanded

“We were just talking when suddenly he started touching me. I mean, really intensely. It was so uncomfortable. The chemistry just wasn't there. I told him to stop, but he just kept touching me more and more intensely... Then he even slipped his hand into my pants.” Ashley told, upset.

“What? What a jerk! So what did you do about it?” asked Sarah.

“Well, I remembered Mom telling us that if a man harasses us, we should go for his balls... So that's what I tried.” Ashley paused briefly before continuing, "Since he was so close, I figured my only option was to grab his balls with my hand. I reached for them, but I couldn’t find them through his jeans. So I tried to ram my knee into his balls ... but he was standing too close, and when he realized what I was trying to do, he grabbed me even tighter... Then, luckily, the bartender came to my rescue and yanked that asshole off me. I was so frustrated that I ran off crying."

“Oh girl, that sounds awful..." Sarah thought for a second before continuing, "But how could you mess up so badly to hurt his balls? I mean, they’re so vulnerable”

“I don't know. It's just... it wasn't as easy as I thought it would be.” replied Ashley.

“Okay, sis, what you need is some training. In case you run into another jerk like that.” Sarah paused, turned to me, and continued with a big grin on her face, “Sweetheart, teach my sister how to defend herself against men. I'm sure you'd be happy to do it.”

Oh damn, she was so right. I already had a boner just because Ashley was talking about balls. And now this? Damn it. I tried to act cool, but I was really nervous.

“Um, yeah, okay, sure. So, Ashley… why didn’t you perform as expected?”

Ashley and I were both a little embarrassed by the situation my girlfriend had put us in.

Before Ashley could answer, Sarah chimed in with a slurred voice, “Oh, come on, she needs some hands-on experience. Come here. Both of you.”

Ashley and I exchanged uncertain glances and she gave me a shy smile before we both stood up from our chairs and slowly approached Sarah. Before I even realized what was happening, Sarah already had a firm grip on my loose scrotum. Her fingers dug deep into my flesh, and waves of pain surged through my body. She squeezed the hell out of my balls. I started shaking and whimpering.

“See, it’s that easy. Not even a second and he’s defeated.” She let go of my scrotum and I sank to the floor, clutching my balls. Then she continued, “Give him a minute, and then you try it.”

Ashley replied, clearly amused, “Oh my god, haha" she had to laugh before she tried to continue speaking more seriously, "Are you okay, John?”

Sarah answered for me, “Yes, he's okay. Just wait a moment.”

Both girls giggled, and after about a minute, I got up again. I stood upright in front of them, ready to have Ashley crush my testicles.

“Okay, sis, now it's your turn” said Sarah

Ashley grinned at me and asked, “Are you okay with that? ... With me squeezing your balls? ... I mean, it really hurts, right?” I loved how she emphasized the word “balls”

“Don't worry about him ... or his balls. You know what? ... He actually likes it.” Sarah said, much to my embarrassment.

Ashley looked at me with wide eyes, and her grin grew even wider. I blushed. Why did Sarah say that? Before I could think about it any longer, Ashley spoke in an enthusiastic tone “You like what?”

I replied, completely embarrassed, “Uh, it's not like that...”

Sarah interrupted me in a loud voice, “He likes having his balls busted. It’s my boy's little weird fetish”

Damn, that was awkward. So now my girlfriend's hot little sister knew about my fetish. But maybe it wasn't so bad after all...

“So you're going to enjoy it when I squeeze the hell out of your balls?” Ashley asked, looking deep into my eyes.

“Maybe... yeah... ” I replied uncertainly.

Ashley laughed. “Haha, that's hilarious. I knew you were a little weirdo.” ... “What should I do, sis?”

“Uh, just try to find his balls and then squeeze,” Sarah said, illustrating her point with a demonstrative hand gesture.

Ashley took a step closer to me, looked me in the eyes, and said softly, “Are you ready, big boy?”

I just gave a quick nod. Her gaze drifted downward, and the next moment I felt her small hand on my scrotum, protected only by my trunks. Her warm hand rested there for a moment, and then she squeezed. I immediately felt that good pain. She squeezed harder and harder until finally my legs gave way and I sank to the ground.

“Yeah, there you go, sis. That’s how you do it,” Sarah screamed hysterically.

Ashley laughed out loud, “Haha, oh my god, that feels amazing. I’m a strong girl!”

The girls celebrated and laughed while I knelt on the floor, clutching my throbbing scrotum. I enjoyed the moment, and it was far from over…

“I think I should do this again. Like, practice is so important,” Ashley said.

“Yeah. Get up, John.”

A little hesitantly, I stood up again. I was so ready for the next round.

“Okay, sis, you had trouble grabbing his balls because of his thick pants, right?”

“Yeah, exactly. I couldn’t feel anything.”

“In that case, you should slide your hand into his pants and grab his bare nuts. That’s deadly."

I couldn't believe my ears. Would my girlfriend let her sister touch my naked balls?

Ashley sounded really happy: “What, haha? I'd love to try that. But are you okay with it...?”

“Strictly for training purposes. Anything for you, sis. I mean, if he has that fetish, why not take advantage of it?”

Ashley looked deep into my eyes again. Then her gaze drifted downward, and the next moment her warm hand slowly slipped into my pants. Instead of going straight for my balls, she stopped at my boner. Her fingers closed softly around my cock. She was swallowing hard. I could tell she was nervous and excited.

“Looks like he’s really enjoying it.” said Ashley

“Oh my God, what are you doing? His cock is mine—you’re only allowed to touch his balls!” To emphasize her words, Sarah gave Ashley a playful but hard slap on the thigh.

"Ouch - Haha, okay, okay. Just a little teasing."

Her hand let go of my cock and moved lower toward my balls. She began rolling my balls between her fingers with moderate pressure. Damn, it felt good. Then she wrapped her warm hand around my entire scrotum. But before she applied any pressure, her gaze wandered back to my face. Then she moved her mouth toward my ear. I felt her warm breath on my skin as she whispered seductively, “You have a huge cock… I wonder if I could handle it.”

Before I could think any further about her words, the pain exploded in my balls. She had a damn good grip and squeezed them mercilessly. I immediately let out a loud scream and my legs gave way. But this time, Ashley didn’t let me sink to the floor. She held me upright by my stretched scrotum.

I screamed, “Ah, fuck, fuck. Please let go.”

I heard the muffled laughter of both girls.

After what felt like an eternity, she eased up on the pressure a little. Just when I thought it was over, she yanked my sack upwards. My balls were stretched to the very end of my scrotum. She held me upright and said in a calm voice, “Look me in the eyes.”

I did my best to cope with the pain and hesitantly looked into her eyes. It was fascinating. She had a sparkle in her eyes that I had never seen in a girl before. She was the woman of my dreams.

Then she increased the pressure again, and my head instinctively turned to the side. But Ashley wasn’t happy with that. With her free hand, she grabbed my chin and turned my head back toward her. Then she brought her face closer. Our lips almost touched, and I stared into her sparkling eyes again.

She said, “You really like this?”

In pain, I replied, “Yeah, yeah.”

In a volume that my sister couldn’t hear, she said, “I like you, John.” She licked her lips slowly and seductively before continuing, “I’m sorry, but I have to finish this now.”

Her fingers dug deep into my testicles, and an intense pain shot through my body.

After a few moments, she finally let go of my balls. I immediately collapsed to the floor and sank into a world of pain.

My whole body was on fire, but I could still faintly hear the girls talking.

As I gradually came to my senses, I realized they were arguing.

“What was that? First you almost kissed him, and now you're licking your fingers you just used to touch his dick and balls?! What’s wrong with you? He’s my boyfriend!”

Ashley tried to defend herself: “No... it's just...”

but my drunk girlfriend wasn't in the mood to discuss and went on, “Shut up. That's it. Get out of here…"

Ashley replied provocatively, “But what about kneeing? I still need to practice that...”

Sarah wasn't amussed at all and shouted back "Shut the fuck up!" than her focus shifted towards me, "And you... Why are you even letting another girl play with your dick and balls? What's wrong with you?”

I knew very well that it was all her idea, but it was pointless to argue, so I stayed quiet and let Sarah keep yelling, "You're sleeping on the couch in the basement tonight. Definitely not with me. I hope the spiders eat you there"

The next moment, both girls left the patio, and I was lying on the floor in pain for a few more minutes before finally heading down to the basement. Damn, my girlfriend was really mad, but at least she couldn't read my mind...

I took a shower, laid down on the sofa, and scrolled through Instagram. Then I got a Snap. From Ashley. My heart was pounding, and I opened it. My dick was hard again within a second of seeing it. It was a picture of Ashley’s half-naked body. Her white panties had a noticeable wet spot. She wrote, “Look how wet I got … It's not just about your huge dick” Then she sent another Snap. A picture of her knee with the caption “Have to train this”

...