As the stream of milk slowed down, Kristen grabbed a different teat to suckle. With her free hand she slowly run up Mary's inner thigh and pressed against her mound through the fabric, gently massageing her here. Mary moaned loudly and unconsciously rocked her hips, thrusting against Kristen's hand. "Please, don't stop... it feels so good."
Kristen went from teat to teat hungrily, milking the udder as she rubbed Mary's clitoris through her clothes; she could feel her moistness seeping through. Mary seemed really on edge - perhaps a side effect of her condition? Kristen doubled her efforts as she felt Mary's nod harden more through the fabric. "Yes, YES! Ooohhh..." A violent spasm ran through Mary's body and she arched her back, then fell to her knees. She glomped Kristen, still moaning and panting. Kristen hugged her closely and they both fell over in each other's arms on the bathroom carpet. She could feel Mary's udder pressed against her body. Mary was struggling to catch her breath.
"You're... you seem pretty good at this, Kristen" she finally said. Kristen smiled and kissed her tenderly in reply. They two of them stayed there for a moment, cuddling. Finally they broke contact and stood up. Mary's udder dangled lazily from her lower belly; it looked smaller now.
"Does it feel better now?" Kristen asked, pointing the udder with a movement of her chin.
"Y... yes, it does". Mary cupped her udder with both hands to feel its weight. "Definitely".
Kristen swallowed her saliva with difficulty; the sight of the udder, Mary touching her cow teats... these turned her on incredibly. She started blushing.
"Mary, I have a question".
"Sure, anything".
"Tell me more about how you grew an udder, I'd like to know..."
Mary grabbed her stuff and ransaked every pocket, looking for the vials.
"Here you go. I received a mysterious package full of these, with some instructions. I don't know who it is from so it's probably a mistake. The more you drink, the more you change, and there's also one vial to return to a human form. They seem to refill on their own, as crazy as it sounds."
Kristen examined the vials closely. Each came with a label, probably indicating the type of effect it would bring. A strange, dreamy look went through her face. After a second of hesitation, she asked:
"Would you let me try one? I find this fascinating... I would love to experiment more, with your help."
"Oh... yes, sure. Help yourself!" Mary replied, leaving all of the vials she had brought into Kristen's hands.
Kristen read each label with much care.