And now the fun part begins - for the Dark Lady at least

Since Chapter VI is rather short, I post it together with Chapter VII

Chapter VI
“That was really fun, Ladies, don´t you think?†She told her silent audience. And now? Now the real fun will commence. Very soon!†“Well, I at least will have fun!†The Dark Lady takes two black torpedo styled vibrators out of her bag.
Each with the diameter of a middle-sized Maglite. Anna feels something inserted between the soles of her arched feed and tied tightly to the ropes around her insteps. The same procedure happens to Kate except in her case the Vibrator is taped in place because the ropes around here insteps are covered in different layers of hose.
Christine feels someone fumbling at the top of her head. The heavy sleep mask is removed.
The sudden light makes her blinking. When her eyes had adjusted, she can see the Dark Lady in front of her.
“For you, the star of the show, I have a special treat! Are you not curious? I would be, if I were you.â€
“Believe me or notâ€, thinks Christine, “I want no special attention at all.†I am perfectly happy as I am, just tightly bound and gagged. You could replace the ripe Hose and Panties with clean ones though.â€
Their kidnapper takes a pad from her belt and tips something on it. Christine can hear the sound of an electrical motor. A humanoid robot strides into the room! It stops right in front of Chistines tightly tied feet!
It was about four feet in height. The automaton moves with precise fluidity and quite obviously was a mature piece of technology, not a clumsy toy. And speaking of toys, its design was arguably cute. But given the circumstances, Christine found the robots somewhat humorous design to be ominous, rather than reassuring. As it turned out, she was right.
"Allow me to introduce my Teaching Assistant," the Dark Lady announced. "Ladies, meet the TK-3500 robot. The Technicians calls it 'ticklebot,' for reasons that will soon become abundantly clear." A diabolical grin crossed her face.
"The ticklebot is quite artificially intelligent, by which I mean it has a lot of on-board memory and independent processing capacity," The Dark Lady lectures.
"But in addition, this one all tied into the The Dark Lady's Network, which is to say, my Academy's network and has access to additional resources, including several expert systems. Its manipulators are strong, dexterous, and sensitive, and have retractable vibrating probes, tweezers, forceps, and Wartenberg wheels.
There's also a new attachment: a pinwheel mini-flogger. The design was my idea, by the way. I'm very proud of it."
“My dear Ladies, why so glum? A little applause would be nice! Oops, I forgot, you are little tied up at the moment. But you can show me your appreciation later in some way!†“And I´m sure we can do something to lighten your mood.â€
She goes behind Christine and the bound woman, feels the heavy mask put on and everything go dark once more.
Kate lay on motionless on her back. The only thing she can do, is wiggling her toes a bit. “Considering how thoroughly I'm tied up and gagged, I'm rather comfortable." she muses.
Suddenly she feels a sharp jab in the heel of her right foot, than in the left. “Ouch, that hurtâ€, she curses silently.
Chapter VII:
A searing hot, burning sensation seems to race like a Tsunami from the soles of her feet right under her skull exploding there like a bomb, she feels as if one hot wave after another race through her body.†Her pulse accelerates rapidly in light speed. Then silence. The eruptions stop as suddenly as they had begun. A short while nothing happens. "The calm before the storm", Kate tries to draw breath into her burning lungs.
From the sounds around her, Kate guessed, that Anna and Christine are subjected to the same treatment.
“Ladies listen upâ€, the Dark Lady addresses her blind, mute and silent audience:
“The Compound I injected you with, is a new development of our Lab. Basically it multiplies the sensivity of your Nerves. You will find that every sensorical stimulation is at least 10 times stronger than normal." “The Essence of the Black Lotus is often used by the Triads.†"I can tell you from personal experience it works!"
She paces, while she explains further, "If you are ticklish already, you will find out, that even the softest touch of a finger will feel like 10,000 Ants crawling over your feet. Simultaneously. Same goes for the Vibrators currently, nestled inside you and between your feet Anna and Kate.
As for you Christine, the touch of the TK-3500 will be intense, to say the least… well, you will learn shortly, I do not want to spoil the surprise too much!â€
"Your Vibrators will follow a complex program. Sometimes you will be rewarded with a nice thundering orgasm; sometimes you will get no release. Totally at random.
Of course the Vibrators in your private parts are synchronized with the vibrators between your delicious soles Kate and Anna, and with the tools of the TK 3500, dear Christine."
She smiles at the delicious complexity of the set up:
"The system is able to measure all physical parameters. Pulse, heartbeat, blood pressure and ensure that you will not get a cardiac arrest; at least my technicians told me so. Though there is – statistically – a margin of error.
All in all, you will have an experience you will never forget, maybe you will lose your mind in the process but most important of all, I will have my fun! Sounds like a win-win-situation don´t you agree?†"Mental sanity is overrated anyway!"
"Talking from personal experience, you bitch", Christine curses silently.
“Let us do a system check before we start in earnestâ€, The Dark Lady grins – and tapps on her IPad.
Anna feels, as if her feet erupt in flames. But the rope which ties her toes to her hair holds fast. The strain is so great, that she feels as if her hair is ripped of her skull.
Kate screams – or she would have, had her mouth not been packed so full. A casual watcher would have seen – or heard – nothing. A Pointing of her toes is the only visible indication about what happens under those layers of rope, tape, hose and bandages
Christine strains against her bonds, which hold her tight on the Chair. A close observer might have seen the well defined muscles of her nylon clad tights and calves ripple. The straps which bind her creak under the strain – but give no way.
“Let the games begin, and may the odds be always in your favour!â€, the Dark Lady quipped. And the games began.