Slut Older Sister Fucked By Teacher

It's been awhile since my fat creep friend used my sister's ass so she's been around my place more often. Thing is I had to go to my old secondary school to get my A level certificates to put with my university graduation certificate. Only issue is the woman who has them is an older woman named miss leah whom I've never got along with. Always miserable and not very nice. My older sister however got along with her greatly. So after accompanying her to get them she disappeared into her office. I thought something was wrong when they were still in there after 20 mins. So after deciding to peek in to see what was happening, I nearly fell when I saw my sister bent over the desk, jeans round ger ankles and ass in the ass with miss leahs 65 year old form plunging a purple strap-on repeatedly up my sister's ass, smiling like I'd never seen. I'm at a loss for words. Even when she came out later to the car with the certificate's I couldn't talk.