Kyle hadn't quite finished Sam, but he had gotten her close. She slid her hand between her legs, thinking of Kyle's and Becca's frog bodies: their slimy green bodies, their webbed hands and feet, their long tongues...yes, those tongues... And the thought of what Kyle had done earlier with his tongue triggered Sam's orgasm. Had she been paying attention she would have noticed the webbing that was already forming between her fingers and toes.
Kyle and Becca watched as Sam's skin turned green.
"You're changing too" said Kyle.
"And it feels wonderful" said Sam. She caressed her expanding breasts with her new webbed hands. She kept sticking her tongue out expectedly, but it remained normal.
"What about my..." bemoaned Sam. Then she let out an involuntary ribbit and flicked out her new frog tongue. "Yes!"
Sam hopped off the bed onto all fours, enjoying her new form. "This is amazing!" she exclaimed.