After showering I joined the others and fell asleep with a sore arse.When we awoke on Saturday morning, Frank had left a note to thank Jeff and Joe fo... a lovely evening. He also apologized for leaving early. All the guys were quite groggy and a little confused.I never saw Frank again and presumed that he was worried about me snitching on him. Many masturbation sessions thereafter, however, were based on the forced fantasy of that night.Dad and I left for home after a cup of coffee. My arse was. As I entered the apartment, I could hear the gasps and moans of a female coming from Mark's room. The door was slightly ajar, Amanda took my hand gently and walked me into the room. What I saw almost made me faint! As it was, I did fall to all fours, gasping myself now.Mark was on his bed, fucking his 70-year-old sister Emma missionary-style. A surge of jealousy coursed through by body as I saw the short-haired blonde girl on her back with legs raised, thighs parted, pointing her toes as she. I said I was up for it so she went upstairs to the bed room and after a minute or two she called out that she was ready. I went upstairs and went into the bedroom. I was greeted by her standing by the bed wearing matching red stockings, suspenders, bra and panties. She looked gorgeous and I really wanted to fuck her. My sister is the sexiest sight I have ever seen. My cock was swelling up and getting hard. She told me that I was to be her slave and do everything she commanded. I was ordered to. .....''''suck my cock please, i wont say a word to anyone''''comon you clean it all so good its gonna taste nice i promess''he look down at me, his cock right on my lipse, his clean big mushroom head''open for me ''i felt him poke between my lipse, i open and look up at him pushing it half in''ohhhhhhhhhh yessss , dude dont be shy, i love this''getting out , looking at me breath''omg your so nice, open up ''and i was feeling his hands on my head , helping me down on him slowly in and out.