Kathryn was exhausted. She couldn't have gotten more than twenty minutes of sleep. But still, she was thrilled. She asked herself time after time if this was all a dream, but it wasn't. It was very very real. She spent the night with Sean Dale-Jameson whom she had a crush on for years and it was more amazing than her fantasies. His body was perfect and her orgasms were more intense than ever. "How the hell did Sebastian pull this off?" She thought to herself. She realized Sebastian would expect her to return a favor and she was willing to submit herself to his passion. She didn't know how much of what happened in Sebastian's room he actually watched through their close circuit TV but even he watched only some of it he probably would be hornier than ever.

Several minutes after Sean Dale-Jameson left she decided she couldn't go to sleep. She was too excited. However, she was very hungry. She was so upset with Sebastian the previous evening she lost her appetite, but now, after burning hundreds of calories during hours of intense sex, she had to have something to eat. She went into the kitchen where Sebastian was already having an early breakfast.

"Hi Sebastian." She said as she smiled at him. "Boy, did I have a good night."

"I bet you did." He said coldly.

"What's up with you?" She said, sensing the hostility in his voice.

"He's some guy you know from TV and just like that you jump into bed with him?"

"Who are you to judge? You don't even have to know a girl's name!"

"Girls should be more careful."

Just as Sebastian was about to reply they heard a voice from upstairs. "Sebastian?"

"Who's here?" Kathryn asked.

"Ahhm, I invited Cecile over last night."

"The imbecile?" Kathryn giggled. "It's been ages since she's been here. What…oh…poor Sebastian was so horny watching Sean and me together you had to call her, ha ha."

"Fuck you!" He replied, just as Cecile walked into the kitchen.

"Hi Cecile." Kathryn said.

"Oh hi Kathryn…I wondered why Sebastian wanted us to go to your room last night instead of his."

"Oh you know Sebastian." Kathryn said. "Always looking for ways to make things more exciting."

"Yeah, I really should be going, my mom will be worried."

As soon as Cecile left Kathryn burst out laughing. "I can't believe you spent the night with this creature. I mean if you were that horny you could have, you know, relieve yourself…"

"Fuck you! I don't jerk off, I fuck."

"What the hell are you so upset about? Am I supposed to be ok with spending the night with Cecile but it's not ok when I have someone over?"

"It's different for guys."

"There you go again! You wanna fuck every hot girl you meet and expect me to just be waiting for you when you get home? Well it can't work that way! That's why we have our deal! To keep this jealousy away from it all. Besides it was you who got Sean to sleep with me!"

"I was coerced to do this! It was unfair of you to get so upset for not going along with your crazy threesome idea!"

"You always talk about how you can't help yourself, right? Well this time I couldn't help myself!"

"I felt like I was being blackmailed! You made me think that if you wouldn't sleep with him our whole deal will fall apart!"

"Sebastian, that's crazy. Since we started with this agreement of ours you slept with like twice as many people as I have, maybe three times as much."

Sebastian knew she had a point. Since their agreement he slept with 16 girls and Kathryn with 6 boys. He suspected Kathryn kept track as well.

"Look, Sebastian I know why you're upset. You know all those other boys were just temporary fun, they were all out of your league but Sean Dale-Jameson isn't. He's hot and millions of girls want him. That's why you're jealous."

Sebastian realized she was right. All those other boys she had sex with didn't matter. She would always crawl back into his bed on Fridays. But she would always remember her night with Sean Dale-Jameson. As he was thinking what to say next Kathryn approached him and put her arms around his neck. "Look, Sebastian, it was awesome of you to get Sean over here last night, I don't know how the hell you pulled this off but you did and according to our deal I am now your, well, slave for the entire Easter vacation so…"

But Sebastian just grabbed her arms and pushed her away. "Fuck you! I have a date tonight. I don't wanna talk to you. Our deal is off as far as I'm concerned!"

And he walked away, leaving her bewildered and anxious.

Over the next few days they hardly spoke to each other. Kathryn became more and more worried with each passing day. Having sex with Sebastian assured his loyalty to her. With him as her ally there were no limits to what she could achieve. Sebastian was popular, handsome and as ruthless as she was. However a jealous Sebastian meant trouble. She knew that if Sebastian would go on to resent her for some time , it would be destructive. Sure she could match his wits and ruthlessness but they would achieve nothing as rivals. Over the past year it seemed they have found the perfect formula for their competitiveness, arrogance, ambition and sex drive. Somehow they were able to have awesome sex together, have sex with other people and still keep the jealousy out of it all. Kathryn realized she made a mistake dragging him into that Sean Dale-Jameson adventure. Sure over the past year they constantly helped each other getting other people into each other's bed but that Sean Dale-Jameson story was a bit too much for Sebastian's ego. Kathryn realized that is she wanted Sebastian back as an ally she would have to get him to have sex with her again. There was no going back.

In the brief conversations they did have Kathryn hinted at him that he'd be welcome in her bedroom but Sebastian just brushed her off, mumbling something about a date or buying busy. When Easter arrived, they both told their parents they preferred to stay at home. After their parents left for the airports she tried to talk to him again saying that Sean Dale-Jameson was just a crazy fantasy she had to get out of her system and as good as that night was, it was all behind her now and she looked forward to having sex with him again but Sebastian didn't nudge. Several hours later Sebastian knocked on her door. She got her hopes up but Sebastian just said their parents phoned to say they landed safely and that he thought they shouldn't have sex ever again.

On the Friday before Easter , Sebastian had another date. His sixth date with six different girls since the night Kathryn spent with Sean Dale-Jameson. It was about midnight when he returned home. When he entered his room and turned on the light, Kathryn was there on his bed. Her right leg was showing above the blanket and it was obvious she was completely naked under the blanket.

"Get the hell out of here Kathryn!"

"No."

"What do you mean no?"

"Sebastian, we had a deal. If I get my wish and spend a night with Sean Dale-Jameson you have me as your slave for Easter. Just keeping my side of the bargain."

"I told you I'm not interested!"

"I don't believe you."

"That's your problem."

Kathryn slowly got out of bed and approached him. "I don't believe you want to throw away what we have because you got a bit jealous."

"It's a bit more complicated than that."

"I realize that, Sebastian. The school year is almost over and I think we both got a bit worried about what's gonna happen with….this. It occurred to me that maybe you thought that when we're in college we won't be doing this anymore, but that's crazy Sebastian, crazy. You think I will give this up?"

She placed her hands on his shoulders. Sebastian remained silent but didn't push her away like he had done over the past week. The truth was he missed the touch of his sister's naked body and they both knew that.

"Look, Sebastian. I watched the tape today for the first time and when I realized you blackmailed him into sleeping with me, well…I can't stop wanting you..,I mean, God, he's a Hollywood star but you blackmailed him just like that…and using his biggest weakness, his attraction to you."

Kathryn began to breathe heavily. Sebastian remained silent and slowly placed his hands on her waist.

"That was the hottest thing ever, brother." She continued.

"I wanted to please you, sis." He finally said.

"I know you did, I know." She said and kissed his neck. His grip on her waist grew tighter and she felt his erection against her thigh.

"But Sebastian", she continued, "What made it so hot was knowing you didn't just do it for me, you did it for yourself. You wanted that week, didn't you Sebastian?" She kissed his neck again as Sebastian nodded at her. "But", she continued, "You wanted it on your own terms not mine."

"I can never let a man touch me Kathryn. Not even for you."

"I realize that Sebastian." She lowered her hands and grabbed him hard. "God I miss that hot ass of yours." Sebastian was about to explode. He desperately wanted her but they knew it wasn't that simple anymore. "Look Sebastian", Kathryn said and pushed her naked body harder against his body, "From today until we start college as a reward for your loyalty to me I will not sleep with anyone else, just you." They stared at each other for a few seconds and kissed, their first kiss for over a week.

"What about Easter, sis?" Sebastian said as he let out a moan. They kissed again and after the kiss with her mouth just a fraction of an inch away from his she said: "That's entirely up to you Sebastian, I mean you're the master, if you want me in your bed all day, if you want me in your shower first thing in the morning, if you wanna go out on a date that's fine, just tell me when to expect you back and in what position." Soon, Sebastian was all over her and in a few seconds he was also naked. As she took his boxer shorts she asked: "By the way how was your date?"

"Fine." He replied.

"D'you, you know, seal the deal?"

"No, she was playing hard to get."

"Stupid girl! Doesn't she realize the earlier she starts having sex with you the more times she'll be able to do it with you?" They both giggled but as Sebastian entered her body their giggles turned to loud moans and sighs. They fell asleep after doing it three times. During their intense love making Kathryn was wondering. The truth was she had no idea what would happen between them after the school year was over however she concluded that to ensure Sebastian's loyalty to her she had no choice but to assure him they would continue to have sex. She had plans to seduce hot rich guys in college but seeing Sebastian every once in a while wouldn't interfere with that and besides, the sex was awesome so why give that up? However, that was a little white lie. There was a much bigger one. On the night their parents left for their Easter vacation and Sebastian told her they shouldn't have sex ever again, something happened. She was depressed, almost crying. So, she contacted Sean Dale-Jameson. He was in town to promote the movie he was filming in their school. She was able to contact his publicist and somehow convinced her she was someone who needed to speak to Sean urgently in relation to a very personal issue. When she talked to Sean she assured him his secret was safe with her and he need not worry. However, that night was so good that when she heard he was in town she had to see if there was even the tiniest of a chance he was interested in seeing her again. She told him she broke up with her boyfriend and was all horny and lonely. Sean told her that he was extremely turned on by what she had gone through to sleep with him and that he loved how free and kinky she was and yes, he would like to get together and that he was staying at a friend's apartment and could spare a couple of hours. Those couple of hours were actually hotter than the night at Sebastian's bedroom and she realized why. Sebastian didn't know about that second encounter so it was like cheating on him which made it so much hotter. And the truth was Sean Dale-Jameson wasn't just some crazy fantasy. She was mad about him and fucking him was way much hotter than fucking Sebastian. If Sean Dael-Jameson had offered her to come and live in Hollywood with him she would leave Sebastian in a second! But that wasn't going to happen so she needed Sebastian back. According to her deal with Sebastian she had to tell about whom she had sex with, but Sebastian called off the deal! Therefore she didn't have to tell him anything about what happened after he said he didn't want to sleep with her anymore. Obviously, now, their deal was back on, but it didn't apply to the time period in which the deal was off. She was in the clear!

At seven o'clock AM the alarm clock woke them up. After taking a few seconds to get her thoughts together Kathryn said: "Hey, it's Saturday why the hell is the alarm clock on?"

"I know it's Saturday sis," Sebastian said. I set the alarm clock just before you fell asleep last night."

"But why?"

Sebastian smiled at her. "Well, sis, I figured the earlier we start today the more we will get done." Just as Kathryn realized what was going on, Sebastian was all over her again. "This is going to be one fun Easter, sis." He said as he kissed her breasts. And they were soon at it yet again.