Spank her

"Turn around and bend over." You tell her, and she obeys, sticking her cute little ass out towards you. "You should be punished for your rudeness." You tell her.

"You're right, I should. I am very sorry I was rude to you." You pleads.

You approach her and flick her skirt up her back, her ass now only covered by a pair of very tight red shorts. You yank the shorts down, revealing Supergirl's tight, perfect ass. She lets out a yelp as you do.

"You may be sorry, now but not as sorry as you're about to be. My powers of spanking will hurt even you." You tell her, convincing her it's true.

You pull a hand back and unleash a spank. It's like spanking steel but Supergirl lets out a small scream regardless. "Please stop, I'm very sorry!" She pleads. You spank her again, not so hard this time, to protect your hand. "Ow!" She yells, "I'm sorry! I'm very very sorry!"

You continue to spank Supergirls ass on the rooftop until you get bored of hearing her apologize. Her face is bright red, even though her ass isn't. "I'm sorry." She says one final time, "I can make it up to you."