Your girlfriend had the idea of turning you into a harpy, which were creatures that could fly because they were half woman, and half giant birds that fly around off of both giant trees, or mountains. With the speed of the harpies, your girlfriend knew that she wanted you to do something fun like that.
Your girlfriend selected that choice, and clicked the icon that showed the silhouette of the harpy she saw, and you began to feel your body change. First your feet began to grow pairs of talons from each of your toes were fusing into 3 toes with sharp black claws, while your heel also grew a black claw becoming full talons. Your own penis continued to shrink while your feet hardened, and became yellow like any other bird who would have those type of feet, and you see it shrink, and become a pussy.