Sister/ sneak up on them and tickle them awake

You creep up towards them slowly being careful not to knock any of the mess lest you wake them up. After making your way to their bed you peer at them trying to figure out who was whom. Deciding the girl on top must be Isabella as she appears slightly taller, thus meaning the one bellow her is Sophia. Now knowing which ones which you aim your fingers for their weak spots. On Isabella, it is her stomach and on Sophia, it's her sides.

At first, you ghost your fingers over them causing them to squirm slightly. Digging your fingers in a touch more makes them release peals of laughter and squirm away from your hands.

WIP