Try and get yourself off. Calmly.

The vibe keeps going. Slow, but relentless. Inevitable. Like...

Slowly, you try and pick up the slack in your bindings, resigning yourself to your fate. The pit in your stomach grows ever deeper at that realization; That you're, unquestionably, submitting to her will. It's not clear if you're growing aroused by that fact, or in spite of it. Hopefully the latter.

You don't have a great range of motion here. You experiment with a pull upwards. The knot pulls back a little, relieving some of its pressure against your little nub. You start to let out a little moan of relief, but it quickly transforms into a yip of pain again, as the pressure off the rope above the knot digs into your mound and applies its own pressure against your clit - this time a tighter, focused jab of pain compared to the broader, gentler push of the knot. You almost lament its absence as you relax your arms again, the light relief that the position gave to your arms not being worth the increased pain in your knees. You have to admit that the varied sensations that the rope is giving you down below are fun, even when a little painful, but the ache in your joints is just something unpleasant to endure.

You repeat the maneuver a few times, trying to find a different angle or method, but discover little. Pulling down relieves some pain in your knees, at the expense of your shoulders. Pulling away from you hurts both. All have the same effect on your poor little pussy. All still hurt, rather unpleasantly.

Finally you decide on a plan of action, of sorts. Pull up quickly with your arms. Slowly release, continuing into a slow pull back with your legs. Pained grunt on the up. Moan of pleasure with the release, swinging into more of a squeal on the downswing. Repeat. Until Nat is pleased? Maybe. Hopefully. You can tolerate the pain for a bit - you're even starting to enjoy it a little - but there's only so much you can do to yourself, before...

You glance up towards Nat. She seems more curious than entertained, her gaze fixed on the screen rather than you. You follow her lead, gazing into the camera lens instead, starting off with more pleading, puppy-dog eyes. She smirks, clearly enjoying that, and clicks the remote. The vibe changes mode again, pulsing stronger but less frequently. No, wait, the frequency is changing. Still slow, but ramping up and slowing down, every few seconds, about in tempo with you. You slow your pace a touch to match the other little nub, hitting peak intensity at the end of each pull, making the feeling just that bit more intense, your moans just that bit lewder.

You try and think of some way to play this role better. Surely that'll get you off quicker. Playing the role of the submissive slut, sex-toy to your sist- no, no, shit, too much. That thought proves to be a step too far, the shame of the situation really setting in. You lower your head, too embarrassed to face the camera. But still keeping up the tugging at your bindings.

You try and think of something else. Pretend you're somewhere else. Not exactly easy. Though, there was that one time, a few years ago. Kinda similar in spirit. Mr Winter's science lab. The whole class gathered around his desk. Me at the front, obviously, but the crowding had me **** up against the corner of the desk, pressing right up against my crotch, while a couple of other people pressed right up behind me. He was showing off some sort of model engine, just running on his desk, bits of clear glass in places showing off how it works. It was a bit loud, and rumbled through into the desk. Even through that awful skirt... I think he knew. I hope he knew.

You're still lost in your reverie when Natalie reaches out to you, cupping your breast in her hand. Eyes wide with surprise, you look back up at her. Despite all that'd happened this afternoon already, you still can't believe she's taking things further. Her eyes are still fixed on the phone as she gently kneads your flesh, more possessive than stimulating, but you get the point, you think. She wants you thinking of her, here in the moment, not lost in your own world.

You return to the routine, and Natalie adds to it; Massaging one breast, then the other, switching hands as she does. She pauses for a moment over your left breast, feeling the thumping of your heart as it beats in your chest that bit harder thanks to her actions. She runs her thumb across the length of the mound, bringing it back towards her thumb. You suspect she's trying to get a hold of your nipple, but hard as they are from all this stimulation, she can't seem to find it through your bra and top.

Your theory seems to be confirmed when her hand withdraws, only to duck under your top and slide up under your bra. She smiles wider as she reaches your little nipple, standing to attention underneath all that fabric. Your pulse jumps up again as you feel her short nails rubbing against the bare flesh of your breast, feeling yet more **** than before. You pause, bracing yourself for her to scratch you, or clamp down, or something else horrible. Instead, she continues to knead them like before, occasionally changing breast when she feels like it, keeping the same hand under your shirt.

The sensations are overwhelming. The vulnerability of your situation, your submissive posing and playing along with her demands, the humiliation of the sock gag and the filming, even the frustration of not being able to stand up and move is all combing to drive you crazy with arousal. Nipples hard, pussy on fire, skin drenched in sweat, pulse racing and breathing heavy through your nose, between moans. The rope up inside you was hard enough to deal with, alternating between jabbing and pushing at your clit, but now with Natalie playing with you, you're so close to orgasming. Natalie focuses on your nipple again, gently pinching it between her thumb and palm. You're right on the edge of orgasm...