(Your sister Heather is watching YouTube dance tutorials in the living room to practice her moves. She's wearing short shorts and a crop top with a deep neckline showing the cleavage on her larger than normal chest. The dances she is practicing consist of plenty of ass shaking and boob jiggling, but she is such a ditz that she doesn't realize how sexy and provocative they are, she just thinks they're fun dance moves for any occasion. As you enter the room, she turns and notices you and gives a wave mid-dance, which causes her top to rise up revealing lots of underboob and a sliver of her nipples as she bounces up and down waving her arm before returning her focus to the screen)