There's an oncoming sound from the hallway behind you. Chained to the floor by your hands, neck and ankles its impossible to see what exactly Bessie is pushing in here in, but it's very large, possibly metal and on wheels. Suddenly a thick monstrous hand grabs around your neck, her powerful bestial grip locks your head in place and the limited blood flow makes you see stars.
"See this little beauty, stubborn little cum cow?" Growls Bessie, presenting what looks to be a immaculately filigreed silver and gold butterfly, but with a needle only an inch long in place of it's body, and it's wings are large handles to fit her massive hands, and attached its end is what seems to be a tiny and ornate bronze chain-like tube apparatus that trails off behind you both.
"Wrought and used by Hephaestus himself. Clever bastard would pump water and ambrosia straight into his veins so he'd never have to leave the forge to eat or drink while working. You though, you're just a typical male. Layers of 'tough' bravado on the outside, but soft and weak on the inside. So you want to act all ballsy, behaving like a huge prick, well then ..."
She trails off and her needle bearing hand disappears out of view behind your head. Your prick gets a brief moment of relief as the cum-milking pump is switched off and removed. But then, there's a quick cold swab wipe at the base of your bloated scrotum. Before you can even react to the chill, there's a distinctly familiar pinching feeling in your sac. 'No...not again' you worry and strain your head against her grip, before it releases you.
You feel it at first, the metallic butterfly clinging to the underside of your scrotum. And as you look down, sure enough the metallic tube links your balls to some brass valve embedded in an immense bejeweled glass tank. Despite it's ornate decorations, it's the size of a minivan and its wheels put it several feet above your prostrate form.
The wheeling noise resumes as Bessie pushes the immense construct around in front of you. Like some baroque tanker train car the tank is filled with what must be hundreds of gallons a familiar orange liquid, but it's darker and cloudy--Bessie's ball bloating alchemy. You feel cold as blood drains from your face. Smiling at your horror, Bessie resumes. "I call this my Hero-breaker blend. You and your goodies are already familiar with my male-maximizing serum, but this is a slow acting, hydroscopic super concentrate, mixed with just a tiny touch of ambrosia and some other fun things."
You gulp dryly, jaw quivering. Bessie's bovine smile darkens. "This stuff is going to infuse and stretch your little sac till it can't hold any more. Then when you body starts trying to dilute the serum stretching your precious milk-sac out even more, because of the ambrosias's healing properties your little udder won't go 'boom.' In fact, I want to see how potent my alchemy can be, because then the change in serum concentration will activate the primary ingredient, so those little cum-quats are gonna grow to take up the slack. And when they grow, there will be so much new tissue to stretch out, so more concentrate will flow in stretching you out again. Endless cycle upon cycle of inflation, stretching and growth. Oh and the best part is, since you love acting like a huge prick, my Hero-breaker has a touch of Essence of Priapus and some medusa venom. So my serum is also gonna make your little milk spout bigger, harder and more sensitive till it drives you insane!"
A deep hearty Cowtaur belly laugh sends shivers down your spine, as the cold liquid begins its slow inexorable flow into your balls.