Stepsister catches stepbrother in bathroom during masturbating on her photo

I love my sister and her body is so hot she have very big boobs and she has very tight pink pussy and she have big ass too once she is taking shower And I have seen her and taken her photo after that I have gone in bathroom and started watching her photo then my penis is erected then I lose my control and started masturbating in bathroom without locking the door then my sister came suddenly and catch me .