You react quickly, knowing you have only seconds to spare before Kat retreats into the safety of the house. Your mind is still reeling from feeling the senses of two separate bodies, but the strength of your teenage libido is enough to keep you remembering how it felt to make Kat’s boobs grow. Focusing intensely, you force her to grow once more, claiming both her rack and her ass this time.
“OoooOOOHHHH!” Kat cries as her already enormous tits swell to double their precious size, and her butt balloons outward to match. Her favorite sweater finally shreds from the neck down, giving the gathering crowd a perfect view of her spectacular cleavage. Meanwhile, your panty self stretches across her bulbous ass as it blows off the cover of her normally modest skirt. If you had a face, you’d be grinning like a madman right now, but the crowd around you definitely is. The bravest and horniest men in the gathering have pushed to the front, and leer in delight at the bombshell you’ve made our of your sister.