Chapter 5: Timing Is Everything

“Please Samantha, don’t ask me to pull out. The first time I came inside you was like a reflex, and the second was a physical reaction to the story you were telling. But this time it’s like an emotional thing. I want to cum inside my little sister and make her feel so good!” Aaron tried to hold this next bit back, but he couldn’t stop himself from saying it. “I need to make a baby in my little sister’s belly. Her big tits rubbing against me are driving me wild, and all I can think about is how much I want to knock my little sister up!” He was totally lost in the fantasy that he and Samantha really were brother and sister. Even though he had cum twice inside her not too long ago, the possibility of cumming a third time in her belly was causing one of the strongest urges he had ever felt sexually. Now that he had admitted what he was feeling out loud, he wrapped Samantha in his arms even more tightly and rocked his hips back and forth, loving the feeling of his hard cock sliding around inside her tight, wet pussy.

“No Aaron, you’ve got to stop fucking me. It could already be too late, but why increase the risk of me getting pregnant?”

“Because I’d love it if I knocked my sweet little sister up and put a bun in her oven. Besides, you’re the one who pulled the knob of my cock inside her when I just intended to tease you. Then you eagerly invited me back inside when the first part of your tale of incest made me hard again. Don’t deny me the pleasure of cumming in your oh so sexy body a third time.”

“I didn’t know what I was doing!” Samantha protested. “I thought a guy busting a nut was something harmless and fun, not something that could get you pregnant. That’s why I was so upset with Kristen, but now I see I owe her a huge apology.”

“But you were so horny, and you felt better after I came in you. And then you felt way better when I made you cum by pretending to be your big brother. Don’t you want your big brother to make you feel good again by fucking you and by cumming in your needy pussy a third time. Even if you didn’t know exactly what was happening earlier, you were craving someone to put a hard cock inside you and cum hard into your fertile pussy just like Vance came hard inside his sister, filling her womb with his child. Let your big brother cum in you one more time.”

After listening to Aaron speak about brothers and babies, Samantha was panting with need just like he was. The pumping motion of his cock in and out of her tight pussy was only making it harder for the teen to resist. Aaron could see her struggling to pick between the desire to let him keep fucking her, knowing that he would cum again inside her and the idea of telling him to pull his dick out. “I mean, that first time felt great, and the second time was beyond amazing. But my mom was a teenage mom, and now Kristen is going to be a teenage mom. I don’t want to be a teenage mom too. Please say you won’t try to make me pregnant again.”

“But it feels so good to shoot your unprotected sister’s belly full of potent sperm! I don’t know if I can stop myself from trying to cum inside you again. Don’t I always take good care of you little sis?”

Samantha’s eyes rolled back in her head, and Aaron could tell she was losing herself to the fantasy of being a little sister getting bred by her older brother. “You do take good care of me big brother, but you don’t really want to knock your little sister up, do you?”

“But I do Samantha! You’re so sexy. It’s hot as hell in here, but you can’t stop mashing your big tits against me. It must be because you want me to notice how you’re built to take care of a baby. You’re not like Kristen screwing a little brother who needs someone to take care of him as much as she does. I’ll take good care of you while you’re carrying our child and keep taking care of you after the baby is born. You’re screwing your big brother, and my big cock makes you feel better than anything in the world. You said you weren’t sure you would want to let anyone else put his penis inside you after feeling mine in your pussy. I don’t ever want to put my cock into another woman after feeling it inside my little sister’s body. I don’t think we’d be feeling this way if we weren’t supposed to be having sex, and having sex is supposed to make girls pregnant.”

Samantha’s willpower was clearly faltering as she confessed her need and started to play along, “This is so crazy, but I do need your cock big brother! And I don’t ever want to feel anyone else inside me ever again.”

“So you’ll let me cum in you?”

“Can’t you stop screwing me for just a minute so I can think? You have no idea how good this feels to me! Oh fuck, I guess I might as well stop fighting it since the urge to let you fill me up with sperm seems to be too hard to control. Do it big brother, try to knock your little sister up again!”

“Yes, yes! You won’t regret it!” Aaron called out as he started fucking Samantha even harder and faster. Even though Aaron was utterly consumed with the desire to knock the girl up, he would have tried to pull his cock out before he came if he hadn’t managed to talk Samantha into his impregnation fantasy. He wasn’t sure he could have succeeded, but he would have at least made the effort. Now he could just concentrate on enjoying the feeling of cumming in Samantha for a third time while trying to bring the girl to orgasm too.

It turned out the sibling roll play and the time it took to convince Samantha to agree to another round of insemination was good for getting her worked up also. She hadn’t been exaggerating about how good his fucking felt to her. She moaned and yelped with every thrust of Aaron’s cock, and she rocked her hips back and forth to meet his invading member. It didn’t take long for her to start gasping that she was about to cum. When her body shuddered and she called out in pleasure, Aaron was ready to fill the girl up with cream. It felt so good to be pumping more sperm into the teen’s belly while she came. Once Aaron’s cock stopped throbbing and pulsing on its own to release even more seed into Samantha’s pussy, she started milking his shaft with the way her body reacted to having an orgasm. Aaron realized that he really did want to knock the teen up! He wasn’t sure if Samantha really wanted his baby, or if he had simply made her too horny to ask him to stop fucking her.

Once the two were recovered from their orgasms, Samantha finally got out of Aaron’s lap and panted, “Oh well, if you were going to knock me up, you probably did it on one of the first two tries.”

He cupped one of Samantha’s perky teen tits and told her, “Well, I am giving you fair warning that I’m pretty obsessed with having unprotected sex with you Samantha, but you’re probably safe today. Your mom told me you just had your period, so it’s not really the right time of the month for you to catch like Kristen did. However, two weeks from now, in the middle of your cycle, that’s when you would be most fertile. Even though I want to pump as much cum into your sweet little pussy as I can, if you really don’t want to have a baby until your older, we’ll start using some protection.”

Samantha looked at me with horror and said, “Yeah, I told my mom I just had my period, I just had it two weeks ago!”

Aaron couldn’t believe what he had just heard. He hadn’t dumped three loads of cum into Samantha when she was least likely to get pregnant. He had dumped three loads of cum into the teen when she was most likely to get pregnant! “Why didn’t you tell your mother more clearly when your period ended? Especially after she said I was going to get you answer questions with my hard cock?” Even as Aaron asked that, and despite having just cum, his cock was getting hard again after Samantha’s revelation about the timing of her last period. The possibility of having already impregnated the girl was such a thrill that his cock was getting ready to try again if he hadn’t already.

“Well, I was a horny bitch until you cured that. On top of that, I didn’t know how dangerous a hard dick was until you explained what busting a nut really was. Jeez, why did Kristen have to use so much slang? Mom was being a pain in the ass asking all kinds of stupid questions, so I gave her stupid answers.”

“I bet you’re kind of regretting that now.”

“I’m kind of regretting a lot of things over the last three months, but I feel like a different person than the one who woke up this morning. If you’ve already knocked me up, I’ll be going through a lot more changes!”

“You mean, before your big brother pumped three big loads of cum into your pussy?”