The two of you enjoyed swimming and playing in the water, darting under the gentle cascade of water as it sparkled in the moonlight. There were kisses and caresses, but no more than foreplay.
Needing a little breather, you made your way out of the water and sat down on a large flat rock. Your girlfriend soon walked out of the water as well, moving with feline grace toward you despite the rough ground. Her long black hair trailed behind her, her nipples were perky, and her skin glistened from the combination of water and moonlight. Already aroused, you felt your erection grow stiffer. She climbed onto your lap, straddling you and putting her arms around your neck. You felt her wetness rub against the head of your cock, teasing it.
You kiss passionately on the lips, then you work your down her neck to her breasts. After playful nibble of her nipple and she can take no more and slides you into her. With the first thrust you feel her nails dig into your back - not something she normally does. You look her in the eyes to make sure everything is okay, but she is clearly eager. Yet as you gaze at her something is happening, almost as if her eyes are shifting their shape. You blink to clear your vision, but now you see cat-like eyes looking back at you.
Before you can say anything, she kisses you, hungry and animalistic. As she rides you something feels unusual under your hands and you run them down her back. You can feel short hair where there was only faint human hair before. Hair...or fur? Your hands go to her butt and sure enough she's growing a tail. A hand goes to her ear and by this point you're not surprised to find it pointed. You give the ear a playful rub like you would with a cat and your girlfriend squirms. Does she realize what's happening? Or does she know and is reveling in it?
You feel something pressing against your chest for a moment before your girlfriend leans back and throws her head back, but keeps a firm grip on your shoulders. You can see she has grown two extra pairs of breasts as part of her feline transformation. Is this the waterfall's magic, eternal beauty? Transformed into a dark-haired catgirl your girlfriend is beautiful, even more than than before. The thought of her being like this forever causes you to climax. Your girlfriend tights around you and lets out an animalistic sound of pleasure from her own orgasm.