The leggings felt snug on Jake, much as they did the first time he'd worn them. He'd slept through his previous transformation. Being awake this time he could feel a tingle of energy through his body. He had been aroused even before putting on the leggings. Now the heavy makeout session, grinding against Kelly, the leggings clinging tightly to him, and the thought of becoming a frog again mean his dick was throbbing for release. If only he'd transform faster!
"I'm already going to..." Jake managed to say before it was too late and he blew his load inside the leggings.
Kelly didn't hear him. She had noticed her leggings seemed looser, especially around the crotch. She was horny and didn't think much about it. Maybe she just ordered a size too big? But as the foreplay when on, Kelly felt something strange. Instead of a desire for something to be inserted into her, she felt something coming out of her. It felt so good as it slid out of her vagina, filling the space in the leggings.
"Oh shit!" thought Kelly. She realized she had just grown a penis. She had bought a pair of male leggings for Jake, planning for him to wear them and become a frog boy while she became a frog girl with the original leggings. That meant....
After Jake finished ejaculating, he felt the strange sensation of his dick and balls pulling into his body until he had a vagina. Then he felt Kelly pressing her crotch against his and something felt different about her's.
"In my excitement I must have gotten the leggings mixed up" admitted Kelly.