The cowtaur drops you down against one of the walls, where she locks your wrists into manacles. You have some freedom of movement with your hands, but as if by design, you can't reach your own cock. Bessie laughs as she watches you test your range of motion.
"This is the punishment for misbehaving livestock. You have to go for a while without milking, and I can't have you doing it yourself. Trust me, you're not going to like this." She reaches over to a table and picked up a clock, fiddling with it to set an alarm. "I think a day without milking will do nicely. More harsh than I would be, but I'll need you to serve as an example." She sets the clock back down and blows you a kiss.
She turns to the minotaur. "You my darling beef-steer, get a stay, but watch what awaits you if you displease me." With a smile she flicks the minotaur's milking machine back on, causing him to sigh in relief. And with that she leaves the room, leaving you alone with your thoughts and the sound of only one running machine.
"Don't worry. I'm working on a way to get us out of here." You're surprised by the almost gentle tone from the minotaur, despite the fact he's glaring daggers at the door. "Name's Aster."
"Aster? I thought you were just 'the' minotaur." Your balls were starting to get uncomfortable, but for the moment you could ignore it.
"Of course I have a name. It's Asterion. But you can call me Aster." His eyes rolled up and he made a shudder as the milking machine got another load out of him, leaving him gasping for a moment. "You might want to get some rest, I doubt you'll get much coming up."
Worriedly you look down at your own balls. Were they larger? It was hard to tell, but once again Aster interrupted your thoughts. "Worrying isn't going to help, sleep. I might need your help as much as you need mine." It was almost as if his words reminded you how tired you were, and your did find yourself drifting off to sleep.
You don't know how long you were asleep but you woke up to Bessie roughly grabbing your shin and pouring some warm, liquid down your throat. At first you panicked, thinking she might be feeding you your own product, or Asters, but then noticed despite being warm is was definitely milk, probably her milk. Stepping back she looks you up and down, patting her udder. "Hera blessed me with extra nutritious milk. It'll keep you and beef-steer over there going with just a quart a day each." She giggles. "And I can make four gallons. My stables are going to be the best." She leans over, looking first at your face then down at your balls. "Oh yes, coming along nicely."
You want to look at what she sees but the warm milk is putting you back to sleep.
The next time you wake up its because of pain. A pain in your crotch. Not a stabbing or hammering pain, but the pain of something being stretched out too far. And as you look down you realize its your balls. Your scrotum is so swollen it's hard to tell there's even supposed to be two testicles. Instead you have just one sack the size of a basketball, the skin stretched taught and smooth. Well, mostly smooth. There are little bumps here and there on the sack but even your pubic hair seems to be gone from your scrotum. Your cock is hard, and a stream of creamy white cum is slowly dripping from the tip, but the slow leak is not doing anything for the pressure. But.. is it bigger, too? Looks like it, or it just might be swollen.
You look over to your only companion, but Aster is still out cold from his warm milk dinner. Sleeping even though he's still being milked. You start trying to get your hands on your crotch, if you could just squeeze your scrotum, or jerk off, you can get rid of some of the pressure, but despite your best efforts you can't reach. Your attempts do raise enough of a ruckus to stir Aster from his milk coma.
"Hey, calm down, little buddy. You're going to hurt yourself." Aster shifts himself into a more comfortable position. "Relax, breathe, you only have three hours left." He nods to the clock.. "Though, you, uh got.." He motions to his forehead, and points to you.
In your panic over your balls you didn't even bother checking the rest of yourself. Touching your forehead you can feel little nubs poking out on either side of your skull, only a couple inches long at this point. "Are those horns?!"
Aster just nods his head, his own multi-foot horns seeming to bob in sympathy. "Small ones. Look like mine when they came in. Congratulations."
You want to glare at the minotaur, but you're too busy still looking yourself over. No, your cock is definitely bigger, and it looks a bit strange, more like.. Your eyes quickly shift to Aster, trying to see his cock through the plastic tube around it. Not quite, but similar. His is humongous after all. "Am I becoming a bull?"
Aster opens his mouth but Bessie walks into the room and interrupts him with a cheery. "Nope! More like a.. cowboy." She giggles at your confusion, but sits down to watch. "I didn't want to miss the best part, you're changing a little quicker than I expected." She licks her lips as she looks at you, no, at your balls, or what should be your balls.
Those odd bumps on your sack have gotten bigger. They're getting bigger even as you watch, until each one is about an inch across, a little divot in the middle. You can't help but think they look like large nipples. Then they start to get longer and horrific realization strikes. You look at your swollen sack, then at the pendulous udder between Bessie's legs.
She notices your look and giggles. "Spot on! Cowboy." She reaches out and gives one of your udders teat's a little squeeze and tug. But instead of milk coming out, it's thick white cum. "An udder full on man-milk." You want to cry, both from the revelation and from the little bit of release that one tug gave you. "The more I leave you unmilked, the more bovine you'll become. Until you're completely a cowboytaur. Then I'll need to think of a new punishment." She looks over her shoulders at Aster. "It'll happen to you, too. Your big strong muscles melting away, your precious balls becoming a big swinging udder."
Bessie hooks you back up to the milking machine, but instead of just the one tube on your cock, there that plus four more, one for each of your new teats. She flips the switch, and you gasp in relief as the machine almost immediately pulls a load from all five connections. Tapping her lips Bessie looks at you and reaches out to give one of the nipples on your chest an experimental tweak. When nothing comes out she smiles. "I could use those for some nutritious milk. Hmm.." Then she gives you a coy smile and leaves the room.