Scrolling video - Found My Sister Masturbating On Cam

I did not expect that. I was just randomly scrolling down my computer and I stumbled upon this file and when I opened there she was all naked and horny ready to finger her tight pussy. I was shocked at first and then I thought that she was actually pretty hot when she was naked so later on I went up to her and I showed her this clip and she was embarrassed and told me not to tell our parents.