"Jaguars."
Ty blushed hard at his suggestion- first Eileen had given her a Brazilian pet name, then she had birthed masses of his babies, now they would turn into the big cats native to his country? "I should've figured," she laughed.
"We don't have to," he assured her. "I just thought it'd be fun if you're OK with it."
"I bet it will," Ty agreed. Kissing him, she added, "I can't wait to have your kits," and wished for them to change.
Seeing Eileen's species alter in front of her was somehow still more striking than seeing her sex alter had been. He grinned and bared his teeth as they lengthened in his mouth and then his face expanded out into a snout. His muscular structure reshaped as he became quadrupedal, his hands and feet became paws while his arms turned to front legs while his back legs doubled over into position, and a long tail extended out above his flattening ass. The body hair which flecked his dark skin lightened to a golden tone and spread all over him, and Ty's eyes widened as she saw his penis develop a more pointy, imposing shape and spines emerge along its surface.
Eileen was now a male jaguar, and had totally relinquished his humanity. Ty could tell hers was fading fast too as the changes overcame her body. Her arms and legs reshaped to a feline structure, and she felt her skull protrude outwards as her teeth became carnivorous. Her breasts gave way to teats which spread across her torso, small nubs for her and her lover's young to suckle. Two different prickling sensations then came over her- the first was the protrusion of her tail from her spine, which she felt herself wag surprisedly. The other was how her skin prickled all over as it began sprouting her fur, and soon she had a pelt just like her lover.
The male jaguar nuzzled his female and she purred approvingly. Until they desired humanity again, the humans they had been did not exist- they didn't even remember the names they had had, not that they would've fit given their reversed sexes. All that they knew or cared about was that they ached to mate, to breed, to reproduce.