Shame or regret for what happened yesterday with my step-sister

The next day, after all that uproar and all that delicious slutty that happened between me and her on top of the living room couch, with her all excited asking me to eat her ass hard and make her big tits swing a lot to the point of hitting each other, she was all embarrassed and even shy, but clearly there was also a naughty smile on the corner of her mouth...