"Screw you," you say, trying to be brave despite the mixture of pain and pleasure welling up in your balls. It's getting distracting -- their growth, while unpleasant, is starting to feel rather... nice. You feel pushed to the point of orgasm, and know that you will cum soon, but in the meantime you feel the instinct to lurch forward and let the machine do its work. As absurd as it sounds, you find yourself wishing you weren't on all fours, if only because you might otherwise feel a bit more dignity. At the moment, however, the futility of your resistance is made clear by your position and by the Cowtaur's reaction.
The beast looks nonplussed for a split second, then bursts into laughter. "I don't think you get it," she giggles, caressing the underside of a testicle. "I own you. You're gonna make me lots of milk, whether you want to or not. Why not make it a little easier on these?" She punctuates her question by squeezing your ball, making you moan loudly. She picks up on this and giggles some more. "See? You're totally helpless. You're gonna be in a lot more discomfort if you don't help me out."
"I said, 'screw you!'" you exclaim. "You can do whatever you want to me -- I don't care! I'm not going to help you. Ever!" A fleck of spittle flies from your mouth and lands on the floor in front of you. There's a sudden pain in your balls: the Cowtaur is squeezing them again, much harder this time. You start to groan, but grit your teeth, hard, keeping the sound from escaping. The pain in your groin stops. Bessie has let go of your balls. You hear her hooves clack on the floor as she begins to walk around you.