A cowgirl

As the pain hits her, Susan sprouts a thin tail with a tuft of rough fur at the tip. Her ears grow larger and fur covered, and a similar white fur with large black spots covers her back. Soon it has moved down her legs and around to her front, her hands remaining the same but her feet becoming hooves. As her breasts become covered in soft fur, they mimic her stomach and expand quickly in your paws. You're soon unable to fit them your large hands, and to your disbelief a second pair begins to grow beneath the first.

This new pair grows even faster, Susan cumming hard on your cock as they do so, and the first pair finally stops growing. By now they are larger than your head, and the new pair matches them soon enough. Finding yourself immensely thirsty, you twist her around on your cock, your knot growing soon after to tie you both together. You press her top pair together, taking both nipples in your mouth and sucking, getting a thick stream of her milk easily. It tastes different than Amy's, more of a kick to it but less sweet, but it is delicious all the same.

Susan moos and screams incoherently through her orgasms, your moving to her second pair not helping her breathe through the pleasure. Your knot reaches full size at more than double the diameter of your cock, and every twitch sends another shiver through her. You begin thrusting into her again with short jabs, her pussy allowing some movement even with the knot as long as you don't pull out too far. "I'm gonna breed you again, Susan. Fill your womb with enough cum to knock up the city. It's all for you, love. I'll be keeping you pregnant for years, I promise."

She screeches in a massive orgasm, and finally finds her voice. "Yes, Master, thank you! Never stop impregnating me! I'll give you so many children and make you proud!" After another long drink, you grin at her, rubbing her already bloated belly before giving her a kiss. "What will your daughter think, seeing her mother bloated with child and turned into such a woman?" Susan arched her back as best she could, shivering at the thought of her youngest child. "She'll be happy to be your mate too once you show her the joy of it, Master. She's a very naughty girl at heart, like her mother."

"Excellent." You pick up the pace now that you have the mother's willing consent to bring her daughter into the harem to show your appreciation. You hit the back of her womb with every stroke, and she squirms beneath you uncontrollably. Her scent bursts with fertility, her body eager for more of your seed even as the eggs your presence had already drawn from her were being gangbanged by your sperm.

Your balls churn up more sperm, aching for another release, and you growl with the effort of holding back. You pick her up, pressing her back to the wall as you pound away. The pictures fall off the wall from the ****, her enormous stomach jiggling back and forth with her equally huge tits. "Aaaah! Yes! Fuck me! Breed me! Pump me full! I need your seed in my womb so bad! Please, cum inside me as much as you can! I wanna be pregnant with your babies forever!"

Susan claws at the wall as you continue your ****, her scent and sounds intoxicating. Her tail whips around between your legs, tickling your balls and pushing you over the edge. The howl you give does not dampen the sounds of the sperm rushing through your cock and splattering against the back of her womb, a full quart of nearly pure sperm bathing her ovaries in the first spurt alone. Susan's stomach expands rapidly once more, gallons more sperm turning her formerly flat stomach into an obscene altar to unrestrained fertility.

Her belly grows to nearly four feet in diameter, outpacing Amy's by a sizable margin by the time you finally finish. Your knot deflates soon enough, allowing you to escape her battered pussy. Setting her on the floor against the wall, you rub your still leaking cock over her, coating her with a large volume of cum that she eagerly rubs into her fur. She lovingly engulfs what of the head she can with her mouth, sucking out the last of your orgasm and swallowing the thick seed gleefully.

She rubs her stomach in adoration, a smile plastered on her face. "Thank you so much, Master. But my daughter will be home soon. I want her to know this kind of happiness, but I know she'll be silly and refuse unless we show her."