As feral Xander pumped into her from behind, Mary braced herself on the couch with her front paws, her eyes closed in ecstasy and her long tongue lolling out to one side. She instinctively held her short new tail to the side, and was unaware that it seemed to be growing in spurts with every thrust of her mate. Long, white fur was pulsing out as well, covering the length of her new appendage.
Xander's speed increased as he reached his climax, and Mary was thrilled to feel his claws digging into her thighs where he gripped her firmly. Hot jets of semen filled her as she howled her pleasure, coming right alongside her mate. The fur on her shoulders and back thickened, covering her in a thick, white pelt and rapidly spreading around her torso and down her arms to meet the fur on her front paws. As they collapsed in a heap onto the couch, Mary reveled in the feeling of Xander's thickly-furred chest resting against her back. His cock still felt engorged and swollen inside her, but she had no desire to move just yet.
Xander nuzzled into the long mane of fur around Mary's neck, and she vaguely registered that his muzzle seemed longer, perhaps the full length of a wolf. Shifting a bit, she turned her head to check on his physical progress and was surprised at her neck's range of motion - her spine seemed to have lengthened between her shoulder and skull, and she could easily hold her head up and look back at her body while spooning on her side with Xander!
Looking down, she could see his grey-furred arms wrapped loosely around her ribcage, his hands still slightly humanoid with long, fur-covered, claw-tipped fingers. Letting her gaze travel upward, her suspicions were confirmed when she realized that Xander's entire head had reshaped into that of a grey wolf: long muzzle, pointed ears and a thick ruff of fur around his neck.
Just then, his eyes opened lazily, and Mary was shocked by their now bright-golden hue.