Open the door slowly and peak in.

From Create Your Own Story

You slowly open the door and peak in. Your younger sister is laying on her bed underneath her covers. She looks like she's sleeping, but there was definitely plenty of time to run back into her room and feign sleep. You walk slowly closer to her bed to see if she really is sleeping. Right before you get to the foot of her bed, your sister stirred, kicking her covers down a little. While you waited for her to settle down, you realized she was wearing a white shirt that was maybe a size too small for her. It clung to her body and didn't leave anything to the imagination. You never realized just how big your sister's boobs were. They were definitely bigger than Nicole's.