This was more fun for me than embarrassing and a turn on for my friend. We went to my house to work on a school project. As we were going in my parents were backing out of the garage on their way to the supermarket. I had to go take a pee but fund out my sister was in there amd heard the shower being turned on. I instantly thought it was the perfect time to get her back for some embarrassing thing she had put me threw a few weeks before. I told my friends and he was all for doing it. So we picked the lock of the bathroom door and went in and removed her clothing and towells. Then we stood there waiting for her to draw the shower curtain. She finally finished and one big swip, pulled the shower curtain fully opened and fund herself giving us a full frontal view of herself. It took her a couple of seconds to realice what had happened, but enough tome to see her boobs and pussy. She was so embarrassed she knelt down on the tub floor covering herself,but we weren't moving and keept looking at her. It dawned on her that if she din't make a move, we would just stay and keep looking at her, so she got out of the tub to run to her room, only to find out we were blocking her way out. We told her she had to hold her hands up and let us take a look if she wanted to be let out. She just stood there blushing with her arms up in the air, till we let her go. I never thought that my sister had such a sexy body. She had a well trimed pussy and midium size boobs with perky pink niples. Later thought that we could have gootten her to let us do some tuching. Oh well, but at least I got her back good and she was HOT.