Experiment 7 is back for further testing. His balls are yet to be used properly and I’m curious to see how much they can take. His balls are tied up very tightly in thin, black rope and he’s secured to poles either side of him. I make sure the ropes are nice and tight. I let him know he’s free to let out a yelp if he needs to. I love listening to the boys’ cries and moans of despair. His balls being tied up so tightly makes them much more sensitive. I breathe lightly on them then squeeze them under my shiny, black heels. I poke my stiletto heels into his balls. I’m not trying to squeeze his balls, though. I’m just trying to push his pain threshold. Although, it is tempting to kick them. I carry on squeezing and tormenting his balls. His cock gets harder and harder. He must be a sick masochist. A weaker man would be making all kinds of noise, but not Experiment 7. He’s a very good test subject. I slap his dick. Hard. It doesn’t seem to soften his erection. In fact, pain seems to make it harder. Very interesting… I rub the head of his cock before slapping his balls. Tease. Smack. Tease. Smack. It must really be confusing his poor brain. So confusing… Pleasure and pain all together. Stay here while I ready you for the next experiment...