We continued the foreplay on numerous occasion that summer. Like I said in the previous story we were home alone a lot. I would come peek at her in the bath tub and she would tease me by sticking her big ass in the air. She was getting rather aggressive.Time and time again I would wake up early in the morning and she would be gagging on my cock. God damn she was good, sucking on my balls, using her hand when her mouth wasn't on my cock. I began to think she was watching porn when I wasn't around.I couldn't complain, being a young boy, my hormones were always raging as were hers. She was starting to get really good at giving head though. I started to wonder where she was getting the lessons from, then one day I found out....... My cousin Chad, had been coming up on the weekends and staying. He was a cool kid, built, descent looking, spoiled, same age as us,but a fucking prick at times.Well one night when our parents had gone to sleep, I was watching a movie in my room and heard a moan. I then walked up to my sisters bedroom door to investigate. I heard it again. It sounded like Caitlyn. I then cracked the door to see what was going on. I then peek in to lay eyes on my cousin standing in the corner, and my sister down on her knees sucking his cock. (They didn't notice me peering in through the crack in the door. )You could hear my sisters mouth, bobbing back and forth,as she slurped up her own drool, and got really sloppy with it. She was known to do that. As I looked on, I could see the excess drool starting to drench her shirt. I've got to admit, at this point my cock was extremely erect seeing my sister in action. Then Chad, my cousin, looked up and seen me looking through the crack, and said "Come in" all non chalet and cool like. Caitlyn looked up me and took it all in stride, she just kept going at Chads cock, while I walked into the room. I then said,"What the fuck dude?" He then responded "Its all good, she's all fucked up from that smoke I brought over, just relax." I looked down at Caitlyn, she obviously was enjoying the moment. Still drooling, and it seemed as if she was picking up pace. I examined Chads dick, he was alot bigger than me at the current time, he had hit puberty earlier than I did. She acted like she really enjoyed the bigger dick. I was kinda pissed about the whole situation but knew I couldn't say anything because of what I was guilty of. Chad then instructed I should eat her pussy, that it would be"cool". I then layed down below her and scooted my face between her legs, next I pressed my tongue inside her warm pussy. By this time she was soaking wet,most likely from sucking dick the last 20 minutes. Her pussy was impressive, she had the perfect clit, and her ass sat right on my chin and her ass cleavage on my chest. Her ass was massive, her back ground in sports and cheerleading served her well. I was licking her clitirous nice and slow like I seen in the movies..and she began to man even louder. I kept wondering if she was going to wake mom and dad up. Chad then pulled back her hair and used it as a handle to fuck her face. He began to thrust quickly into her mouth, while she still continued to slobber. From my view it was great looking up at this, she then began to drool downward on to my face a little bit. At the time being I didn't care because her pussy taste so good in my mouth. I then felt her starting to shake and she moaned extremely loud with Chads dick in her mouth. She then motioned and pushed my head from her crotch. Caitlyn was acting selfish and guilty now that she had her orgasm. She then tried to pull her mouth off Chads dick and he grabbed her by the back of the head and said ," Your not getting away that easy".He was strong so he man handled her and put her mouth back on his cock. He then told her to rub her pussy while she gave him head. She did exactly as told. I watched in awe how she responded to commands from him. Then as he started to go faster and faster calling her names while he was doing it, "fucking bitch", "little whore". He then pulls his cock out from her mouth and she automatically sticks out her tongue like a platter ,he shoots stream after stream all over her pretty face and green eyes. Then she puts his dick back into her mouth sucking out the last drops. I then walk up eagerly to get my turn, and Caitlyn says "Not tonight, I don't want you anymore." She then gets up off her knees and rushes off to the bathroom. -I knew from that point on, I was going to have to take control of this bitch to make her do what I wanted her to do. I had to find a way how.-