What Sam visualized was Mark, hunched between Chrissy's wide spread legs, while his ass bobbed up and down and his undoubtedly nasty cock slithered in and out between his sweet sister's pussy lips.
In short, Sam got horny and pissed at the same time. He laughed a dark laugh.
"That's stupid," he said. "Every guy who ever looked at you wanted to get in your pants."
"That's not true!" squealed Chrissy, her eyes wide at how crude Sam could be.
"That's what we're trying to tell you, honey," said her father in his reasonable voice. "Men are built to want to have sex with beautiful girls. You are a beautiful girl. Ergo, men want to have sex with you. Boys too," he added.
Chrissy didn't believe it for one minute. She had an idea. "All men?" she said, acting like she might believe it.
"All men!" said her brother and father together.
"So ...." she preened. "You have wanted to have sex with me too?" She clasped her hands behind her butt and grinned at her father. "I mean you are a man, right? And you did say all men," she finished triumphantly.
She turned on her brother. "And you too!" she giggled now. "Obviously you too have been practically consumed with lust for your dear sister." Now she laughed out loud.
Then she stopped.
Neither man was laughing with her. In fact, both looked decidedly guilty!
"You'll never believe me until you see it for yourself," said her father. "So, you and Sam are going on a date. Tonight. And I'll be with you, but I won't say anything, unless you two are supposed to do something and I see you aren't doing it. Okay? It will be a pretend date, but Sam will show you what boys do on dates with girls. Then you'll understand," he said with finality in his voice.
"But Sam's my brother!" said Chrissy.
"And Chrissy's my sister," said Sam, somewhat unnecessarily.
"That's right, and that's the only reason I'm allowing this," said Stephen. "You must be made to understand how dangerous it is out there. Now. Both of you. Go get dressed for your date. Each of you choose something you'd like to wear on a date with someone you really like."
Both teens trudged off muttering about stupid ideas. Stephen went to each room to ensure that his orders were followed. He went to Sam's room first. "Sam, I want you to pretend she's just another girl you met at school. Treat her just exactly like you'd treat any other girl. Okay?"
"Sure Dad," said Sam, while mentally saying, "With you watching ... right."
Then Stephen went to Chrissy's room. He walked in to find her dressed only in her panties.
"Daddy!" she yipped and covered her precious breasts with her dainty hands.
"Oh! Sorry, sweetheart," he said, looking at the floor. "I know Sam is your brother, but I want you to pretend he's some boy you wish I would let you go out with. And dress like you were going out with that boy, not Sam." Then he left, before she could see the tent in his pants. While that might have supported his contention about "all" men, he was a little embarrassed about it right then.
Sam got back to the living room first. He had on his team sweats. They were talking about football when Chrissy started down the stairs. Both men looked up and their jaws dropped. Chrissy was dressed in a micro skirt with a matching halter top. The halter top had a deep vee that dropped well below the mid point of her breasts, ensuring that everyone knew no bra of any kind was involved in this outfit. Sandals completed her ensemble.
Quite suddenly Sam didn't have very much trouble at all pretending this was just some girl he was taking out on a date.
"Wow," he said. "You look hot!" He flinched and looked at his father out of the side of his eyes, but his dad was staring at Chrissy too.
"Yeah," said Stephen in a dull voice. Then he shook his head, as if trying to drive some thought out of it. "Okay, now you guys have already had dinner. Where would you take her now, Sam?"
Sam knew he would try to get his date out at the beach, where it was quiet and remote and romantic. But he couldn't say that in front of his dad. "I'll uh drive around. I guess."
"Okay then," said Stephen. "Let's go." They went out and got in the car. Chrissy and Sam in the front, and Stephen in the back seat. Sam started driving. He didn't know where to go since he couldn't go to the beach. He was getting frustrated. He could be out with a real girl tonight, but he was stuck with his sister. He glanced at her. Her micro showed her legs almost clear to her pussy. He gulped. She scooted over and leaned one hot breast against his arm. It felt soft.
"Aren't I supposed to sit here, beside you?" she asked in her sweet voice.
"Uh, yeah ... sure," he said. This was crazy. They will be out here for hours. He decided to call his father's bluff. "Actually, I would be taking my date out to the beach. There's this cool place where I take the girls. You know, to talk ... and stuff."
"Now that's more like it," said Stephen. "Let's go."