Vibrator birthday bondage

I had the idea last week, during a conversation we were having about our favorite songs. She told me that there was one particular song she found "eargasmic". I asked her if she'd like me to help her enjoy it even more, and she agreed.

She was able to book a few days off work, and so the following morning she arrived at my dungeon. I asked her one more time if she was happy to go through with my idea, and warned her that once I'd strapped her up, there would be no way for her to communicate, so a safe word would be pointless.

She was still enthusiastic, so I asked her to strip naked for me. I then blindfolded her and led her into the cabinet, where I began fastening the straps tightly around her body. I locked her arms and legs in place so that she would not be distracted by the thought of moving them, and I even suspended her body in the air, just so that 100% of her attention would be focused on the sensations in her ears and crotch.

Every morning and evening, I open the cabinet to feed her a smoothie that contains all the nutrients she needs, along with a concoction of supplements and drugs which keep her as sensitive and aroused as possible. I then remove her butt plug and allow her to defecate, and then I clean her up. Otherwise, she receives absolutely no other attention or stimulation, other than the music in her ears and the vibrator in her pussy.

I created a playlist for her, and put it on shuffle. Whenever her favorite song starts, the vibrator buzzes, and keeps going until the song ends. Her song comes on roughly once an hour, but during every other song she is kept in suspense, never knowing how long it will be before her next orgasm.

I had the vibrator set to high for the first day or two, and then gradually reduced it to the lowest setting. Her song came on midway through feeding/cleaning time this morning, and even though the vibrator barely moved at all, I watched as her body convulsed just as intensely as it had done the moment I locked her up and started her torture. I'll switch the vibrator off entirely tomorrow, and if my experiment is successful, she will orgasm involuntarily even though her crotch is receiving no stimulation at all.

I'll unlock her on her birthday, which is coming up in three days' time. I can't keep her locked up any longer anyway, since her muscles may start to atrophy if she is unable to move for too long. Unbeknownst to her, I have gone to the trouble of organising a surprise birthday party for her, since she is obviously unable to make any arrangements herself. I'm sure after so long in isolation, she'll really enjoy seeing her friends and family, and celebrating her birthday with them all.

...especially when her favorite song comes on.