Dave close his eyes and braced himself. He'd just fucked up, and he knew it. While it didn't seem like anything could get worse, he knew Nurse Violet could find a way. He didn't want to see it coming, but he'd just spoken without her permission and he feared it would be bad.
Suddenly something clamped around his head and his eyes flew open in surprise to it and the sudden blast of noise only to see the nurse stepping away, shaking her head. She paused a couple feet from him and spoke at him, but he couldn't hear what she said because the headphones or whatever she'd put on his head was playing some kind of loud, electronic music. She spoke to him again, her head cocked, and then with a parting, almost playful motion, gave his balls another slap and turned back to the two guests at the door. He saw stars and his whole body seemed to ache as the pain radiated upwards so he didn't see exactly what happened, but when he could focus on the door again, there'd been a change and he saw what he'd feared.
When she'd opened it, two people had been waiting outside and he immediately recognized them as the woman whom he'd first encountered outside another shop that had an exhibition in progress and then again when the curtains had been open. Her wide eyes had been the last thing he'd seen through the window before Nurse Violet finished closing them, her big irrigator strap-on buried in his guts and cum on his stomach. The idea of strangers seeing him in this position was bad enough, but this stranger had seen him as a person first out in public, he couldn't explain why it seemed to much worse or intrusive, but it was there.
But while she remained in the doorway, the other person who'd been standing there a few moments earlier was gone. Her friend, the other woman, she was missing and Dave wondered why for a moment but then Nurse Violet was apparently inviting her in and he felt his stomach drop. The woman walked in and walked around the room, looking at the things hanging on the wall, the table, and finally at him as he lie on his back, naked, feet held apart and bound to the elaborate examination table. She blushed and laughed, looked away, then back at him and his insides twisted. She was... a normal person, and she was seeing him like this and....
He must have made a sound because the nurse walked behind him and a few seconds later, she loomed over him from behind. Leaning over him, she brought something up to his mouth and expertly popped something in, something big enough to push his jaw open. It felt like it was made of rubber except it didn't taste like anything, so a distant part of his brain guessed it must be silicone too, and as he worked this through, she lifted his head and some of his hair was pulled for a moment and then he realized she'd snapped a connector shut and there was now a gag in his mouth.
His eyes got wide and he struggled against his bonds, worried he wouldn't be able to breathe if his nose got clogged or swollen but after a moment, he realized he could breathe freely through the gag. It must have a big opening in it and while he knew he could probably make noises, he wouldn't be able to form words. A sudden panic began to build that if he couldn't say anything, there'd be no way for him to use the safe word she'd given him at the beginning of the session until as if reading his mind, a moment later he felt something soft pushed into one of his hands and he gripped it. He couldn't see his hand, but as the thought formed, one of the headphone cups over his ear lifted for a moment and Nurse Violet spoke into it so close that he could feel it.
"If you drop this, I will take that as your safe word and we will stop. Do you understand?"
He nodded as best as he could and, apparently satisfied, she set it back on his ear. The thumping dance music filled his world again and he could only watch as the woman spoke to Nurse Violet who responded, but he couldn't tell what they were talking about. The woman glanced at the door then back at him and got a funny look on his face and he felt like he was going to die. He couldn't explain why he felt so much more naked in front of this stranger than Nurse Violet and he could only imagine maybe it had something to do with her not being a professional. He knew his face burned with shame.
He wished he could tell what they were talking about but with the blasting music, there was no way to tell.
After a moment, the woman nodded hesitantly at something the nurse said and turned around to find a spot in the corner where she leaned against the wall and watched. What she was watching, he couldn't tell until he saw some motion off to his left and then tracked Nurse Violent coming into sight again. She walked between his legs and held something up for him to see briefly before lowering it back out of sight and doing something.
It was unmistakably a butt plug, he knew that much, but it was chrome colored or metal and had a wire hanging from it for some reason. After a moment, she lifted it back up again and he could see it was glistening wet and felt he knew what was coming next.
She must have liked what she saw on his face because she smiled and lowered it out of sight and a moment later, he felt it nuzzle up to his exposed asshole. Her other hand pulled one of the cheeks to the side and after a moment, the plug began to slide up into him.
He didn't know what the plan was because he felt so drained after the milking session and almost as if he wanted to just be done, but as the plug stretched him, he felt a twich in his cock and rested his head on the padded back, giving in. He knew he could end this if he had to but... he held onto the thing in his hand.
He could feet her twist it a couple times as if spreading the lubricant more evenly then, with smooth but firm force, she pushed it in. He took a breath to yell or groan or something, he wasn't sure, then the widest part suddenly popped past the elastic ring of his asshole and he groaned as his butt sucked it in and it burrowed inwards, coming to rest against his prostate.
Opening his eyes again, he looked down and saw her working with something out of sight. He couldn't tell what it was or could be, but after a moment, she stood straight and smiled coldly at him. He wasn't sure what was going on, but that smile made him nervous.
Looking at him straight in the eye, she slowly lifted one of her hands up so he could see it clearly, see that she was holding some kind of device with her thumb on a button. She raised an eyebrow as if visually asking him a question and without thinking about it, he shook his head.
She laughed, then made a show of reaching over with her other hand, extending her pointer finger, and looking back into his eyes, pressed it.
His body jerked as all of the muscles in his ass suddenly contracted against his will, then released. He whimpered, he'd never experienced anything like this before. Smiling at his reaction, she tapped the button again and again, his sphincter contracted hard, squeezing the butt plug in his ass and, as a side effect, shoving it against his prostate.
He moaned but through the gag holding his mouth open, it must have sounded like talking because she took that free hand and swatted his testicles again then pushed the button firmly for a few seconds. Even with that sudden twisting pain, he could feel his fully erect penis slap his stomach as the muscles in his ass contracted hard and squeezed the plug against that walnut sized that was still somehow sensitive.
She began to develop a pattern, on for a second or two then off. On, then off. Each time, his ass squeezed it against his will and he slowly began to understand it was using an electric current. He couldn't feel a 'zap' or anything, it was just his muscles firing against his control, like he was losing control of his ass and being used as a puppet.