Blackmailed Sis'

With out parents away for the weekend, it was just myself and my older s****r Jenna (19) at the house.
The first night on our own, I was shocked as I looked out the window as I saw my s****r bringing her boyfriend back into the house, normally she would not do this. I gently opened my bedroom door and saw my s****r taking this guy into her bedroom.
It did not take a lot of working out, what they were up to. I could hear heavy breathing, moans and groans, she was getting herself well and truely fucked by this guy, as I listened at her door. I went to my room and wanked myself silly imagining what they were up to.
Saturday morning I awoke to the sound of the shower going. I got up and looked into Jenna bedroom, the room was a mess, Jenna's clothes all over the floor, the guy had obviously had his way and gone.
As the bathroom opened, Jenna came out and saw me stood there. 'I'm telling Mum, you had a guy here last night!' I said to her. Jenna was furious and gave me a mouthfull of abuse as she went into her room and slammed the door.
I want back to bed and watch the t.v. for half an hour or so.
Then Jenna opened the door and came in having got dressed. 'Please don't tell on me, I'll do anything, I'll be your slave for the day or something?' she shrugged her shoulders.
I pondered, I was furious with her, that she had cheated on Mum and Dad's trust, but thought I could have a little fun myself. I agreed and told her she could tidy up my room. I stayed layed on the bed as she started putting things away. Jenna was pretty fit for a s****r, all my mates have at one time told me they would like to do rude things with her.
I watched for five minutes or so and told her to stop and stand in front of the bed. 'You're doing a good job but it could be better", she looked at me and asked 'how'. Not sure how this would go, I kind of mumbled it, 'strip to your underwear!' not quite hearing me, she asked again, this time I said it with a bit more conviction, 'Strip to your Underwear!' she called me all the mutherfuckers under the sun, but I again mentioned telling Mum and Dad.
She looked daggers at me as she took off her t-shirt revealing her bra, she sst on the bed as she removed her tight fitting jeans, she stood up in her briefs.
I smiled as I looked at her curvy body and told her to carry on tidying up.
I stroked my cock under the duvet as I ogled her body. She kept looking over at me giving me dirty looks.
She had pretty much tidied up by now, I told her to stand in front of the bed again, 'take off your bra' she called me a dirty bastard etc as I just grinned. She paused for a few seconds, tutted, before reachind behind and unclipped her bra, which she removed, covering her boobs with her arms.
'Hands on head!' I ordered, she shook her head as looked at me in disgust. She then put her hands on her head, exposing her bare breasts to me. I let her stand there for a couple of minutes as I looked at her tits.
My heart was pumping as I thought of what was to some next 'Now take off your panties!' I wasn't sure she would do this, but I wanted to see how far I could go with this situation.
Without a question, she brough her hands down and pulled her knickers down, stepping out of them. She picked them up and chucked them at me. Before putting her hands back on her head. My eyes popped out as I looked at her hairless slit.
My cock was throbbing under the duvet. I picked up her knickers and examined them. I then looked my s****r in the eye as I sniffed the guset. She shook her head in disgust.
I then told Jenna to turn around and part her legs and then to bend over. She did this as I stroked myself. I then told her to reach behind and pull her butt cheeks apart. Again she did this, exposing her pussy, slightly parting and her cute little arsehole.
I rearanged myself in my shorts as I moved to the edge of the bed and had a good close up look at Jenna pussy and arse. I imagined what her boyfriend had done last night.
I told Jenna to get on all fours on the bed, so I could examine her better.
She got on the bed looking like a dog on heat. I put my thumbs each side of her pussy and spread it open as I looked into her pink cunt hole. My cock twitching even more. I rubbed her clit and checked out her little pee hole before pushing a finger into her cunt. 'You dirty bastard' she replied. It felt to good, so hot, wet and tight. I fingered her a little adding a second finger, my thumb touching her anus. I asked Jenna if she takes it up the ass? Jenna replied no, she would have to know a guy a long time to do that. I smiled and replied with 'well you have known me for s*******n years, I guess that means I can fuck you up the ass!'
At this point I pushed my thumb into her anus. She shuddered as it went in. I enjoyed feeling her pussy and arsehole for a few minutes, before positioning my self around her face. I dropped my shorts and pulled my foreskin right back as I thrust my dripping cock towards Jenna's mouth. She looked up in horror at me as I told her to suck it. She hesitated before taking it in her soft wet mouth, and started to suck me. Wow! I was in heaven, as I looked down and watch my cock slide in and out of her mouth.
I was so close to cumming, but had other things I wanted to do, so pulled out. I got myself right behind her and pushed my cock up Jenna tight cunt, oh my got was this really happening, it felt so good, but the last thing I wanted was to get my own s****r pregnant, so I pulled out and this time pressed my cock against her anus. Jenna looked over her shoulder at me 'what the fuck!' but as soon as she utter the words, my cock was entering her arsehole, by was it so tight. I slowly guided it deeper into her, before starting to fuck her in short thrusts, my balls were fit to burst as I buggered her. Suddenly I could not last any more, as I felt myself lose control and my hot spunk shot deep up Jenna's rectum. This had gone better that I imagined and it was still only Saturday morning. More fun to be had before our parents returned