All characters in this story are 18 or older. The names have been changed to keep their secrets.
****
Part 5 - The Rules of Boating
The next weeks were amazing. Jack and Kate had made the most of the time that they had together. They would kiss in the morning in the bathroom sometimes until both of them were so turned on that they forgot the time, and would sometimes be interrupted by Amanda calling up the stairs for them. One morning, Kate had dropped to her knees and completely sucked Jack off before going to school. She still couldn't swallow a whole load, so she spit into the bathroom sink, but Jack didn't care. Sending his little sister off to school with a wet pussy after sucking him off was good enough.
At night, Kate would often sneak into Jack's room, wearing next to nothing, and start a long make out session. Jack loved kissing Kate and touching her all over her body. Kate was ok with Jack taking off her underwear now, if he was going down on her. But she had announced her rules to him about not poking at her so hard with his thingie. It was against the rules for him to be naked and get on top of her while she was naked too. One of them should always have their bottoms on. She was a good girl after all. Jack didn't mind Kate's rules. He was still cumming a lot and getting to explore her body.
In the shower, Jack would sometimes put his hard cock between his sisters legs and move back and forth, while he rubbed a soapy finger around her butthole. Kate loved this more than almost anything. And somehow this wasn't against her rules. Kate would feel the sensations building in her body, but she still hadn't had an orgasm yet. Jack asked her about it, and she had explained that it was harder for girls sometimes. They talked some about the whole "letting go" thing some more, since Jack was wondering if that was it. Then there was the issue of never really being alone, because they were always worried about who would come home.
This didn't stop Jack from trying to get Kate to orgasm. One day he walked in on Kate changing in her big closet. He pulled her panties down, and she bent down with her hands on the hamper in her closet. Jack got down on his knees and put his hands on Kate's beautiful bare ass. He kissed all around it as Kate giggled. Then he gently pushed her cheeks apart and his tongue darted for her tight little hole. Kate would gasp, as she still couldn't believe how he wanted to lick her there. Jack would rock back and take in this view. He would use his fingers to open up his little sister's pussy lips and then dive back in. Kate was becoming a big fan of oral, as it brought her closer to what she thought sex was supposed to be all about. The intimacy of a boy between your legs and the trust there.
And Kate knew something that Jack didn't know. Amanda had taken Kate to her gynecologist after Kate had complained about some irregular periods. Kate was surprised when the doctor put her on the pill, saying that it would help to regulate her cycle. Amanda was actually relieved, because she remembered what she was doing when she was Kate's age. Amanda started talking to Kate about sex on the drive home and reminding her that the pill didn't protect her from diseases, only from getting pregnant.
"Jeez, mom! Can you drop me off at the school gym? I'm supposed to bang the whole football team today" Kate said with a wicked smile on her face.
"Katherine!" Amanda objected.
"You don't have to worry about me, mom. You raised me right", Kate said, rubbing Amanda on her shoulder.
"Well, if you ever want to talk" Amanda didn't even finish her whole thought. She wouldn't have told her mother about when she gave a guy a blow job or anything. "I'm here for you, Kate. And I love you."
"Thanks, mom."
As summer approached, Kevin asked Jack over breakfast to go to the boat dock and get the boat ready for the season. Kevin was always at the restaurant, and getting everything working for the season on the boat was a big job. Jack said he would do it, but that he needed some help. Amanda was at the table and asked Jack which of his friends he wanted to take along. Jack thought for a moment, "I'll get Kate to help me" he said.
"Good luck with that" Amanda said with a snort.
Jack thought he could talk her into it.
Later Jack pulled out his phone.
J: I know what we're doing 2 days from now.
K: You do?
J: We're going to get the boat out. You and me.
K: Oh shit.
J: Come on. It will be fun. We'll get it uncovered and set up. Go for a short cruise and a swim. No one around to bother us.
Kate thought about it. She would need a new bikini. Now that she was waxed down there, she could wear just about anything. She also thought about the bikini that she would be willing to wear around just Jack. This called for some immediate shopping.
K: Ok. I'm in.
Two days later they were driving out to the dock with a cooler packed with lunch and some beers that Jack had got his hands on somehow. The boat was a 40 footer. It was mostly open in the back and had a cabin down below in towards the bow. There was a galley area with a table, a tiny bathroom, and a stateroom with a bed in the bow.
Jack was already thinking about what could happen when he saw Kate in her short shorts, and a loose tank top that gave a preview of her white bikini underneath. After the initial hard labor of removing the cover, stowing it, getting the engine started, getting fueled up, filling the water tanks, and checking all of the major systems, it was finally time to head out.
The dock was close to the outer parts of the bay, so it wasn't long until they were out in the gulf and moving at full power. Kate went down below, and when she emerged, Jack's jaw dropped. She was wearing a tiny white bikini, that had little ties around her neck and back, and also two at her hips that held on her bottoms. Kate's cleavage was something to die for, and her little ass was barely covered by the low cut bottoms.
"Amanda was not with you when you bought that" Jack said with a smile.
"What she doesn't know won't hurt her. And I thought you would like it."
"You thought right." Jack said, as he took off his shirt and got ready for a day of fun in the sun.
Jack took the boat out along the sand keys that lined the coast. There would normally be some guys fishing in along this path, but it was maybe too late for prime time, or an off day, but they were completely alone. He guided the boat into a little cove that was lined with palm trees. The water was fairly shallow, and Jack jumped out to secure the anchor. Kate blew up one of the floating loungers with the air pump, and tossed it in the water. She followed right behind it.
