Warning: the following story contains graphic descriptions of very casual sex. If that is not to your taste, I would suggest you read something else. This is all complete fiction. I would never condone or tolerate in real life the behavior described in this story.
All characters are over 18 years of age.
I would recommend reading the previous parts of the Evolution series before you continue, as you may enjoy it better if you know the full backstory.
-----------------‐-------------------------------------------------------------------------------------------------------
"We need to start tapering from now Dad," says Ben. We've just finished a tough hill running session and are in the middle of stretching in the backyard at home. It's a nice sunny Saturday morning, perfect for a getting outside for some exercise.
"What the hell is tapering?" I say, not having a clue what he's talking about.
"We only have one week to go before our race. Tapering is gradually cutting back on training so we're fit and fresh for the big day," Ben explains.
I can't believe the progress I've made since we started this. I've lost weight, I feel much healthier in general, and it's been great spending so much time training with Ben, and Claire when she joins us.
"So we need to do less running to run better next week?" I say, a little skeptical but kind of getting it.
"Yep, that's how it works Dad, trust me," Ben says as he laughs a little.
My life feels like it's been turned upside down recently. I've started screwing my sister-in-law Emma, my wife's Laura's younger sister. I'm also sleeping with my son Ben's 19 year old girlfriend Carla. I'm obsessed with fucking my boss Jean. To really send me into a spin, my daughter Claire wants me to ejaculate into her panties on a regular basis, and she wears them around all day afterwards. And my wife Laura knows all this, and she seems to enjoy it almost as much as I do.
That's the confusing thing, I'm having the time of my life. But it's a lot to get my head around, especially the thing with Claire. Apart from running, sometimes the only other thing I can do to get away from everything is fuck a random stranger. It's like an escape. But being honest, I don't really want to escape from any of the women in my life, I just need a little break sometimes.
Getting out in the fresh air for runs has really helped clear my mind of all the confusing emotions I've been having.
Luckily my sex drive is through the roof. My sexual capabilities have evolved immeasurably since our world changed over three years ago. I seem to have a never ending supply of cum for one thing. My loads do get smaller as the day goes on, but the urge for sex never seems to diminish very much, it only abates for a short time after fucking.
My confidence has improved a huge amount since Ben and I started our training. I've lost a lot of weight, my belly is almost completely flat now, and I've noticed my muscles are getting toned all over, which is probably down to the weight training Ben has convinced me to do as part of our workout plan. Women are paying me more attention than I'm used to, which is a real buzz.
"Dad, remember that day when aunt Emma came over and we, eh, you know," Ben says suddenly. We've finished our stretching and are in the kitchen drinking some water. He's talking about me and him both fucking his mother's sister, then his mom walking in on us. All that was messed up enough, but then Laura made Ben shoot his cum into her mouth. She said it was so Emma wouldn't get pregnant, and to save the furniture. But really that was bullshit. Laura can be into some pretty kinky stuff in the bedroom, and I think she just wanted to eat her son's cum.
"Sure, I remember. What about it?" I say, wondering where he's going with this.
"Well, when Mom told me to, em, cum, into her mouth. Did that bother you?" he says, looking at the floor.
"It was a bit weird," I say honestly. "But your mother makes her own choices. If she wanted to do that, then that's up to her."
"So you're not mad at me?"
"Ben, I screw Carla whenever she's over here, who am I to talk?" I say, and he laughs. "Look, you're an adult, and so is your mother. Yes it's probably wrong, but I know sometimes things that are forbidden like that can be the hardest to hold back from. Your mom is a very attractive woman, I understand what you might be feeling."
"OK. Thanks Dad," Ben says quietly.
"I'm going to take a shower. I don't want you worrying about anything, OK?" I say to him, putting a hand on his shoulder.
He smiles back at me, looking a lot more relaxed.
-------------------------------------------------------------------------------------------------------------------------
I've been trying hard to hide my infatuation with Claire, which has intensified since she asked me to cum into her panties, while she was still wearing them! Seeing her pussy, being so close to her body, cumming for her, it's changed me forever I think. Every time I see her around the house I get such a strong desire to do it again. But since that one time, she hasn't asked me for a repeat in-person performance.
When I jerk off into her panties now, which she still leaves on my bed a few times per week, all I can see is her standing in front of me stretching them out for me to shoot into, her bare pussy on show. It was the hottest, most taboo thing I have ever done. And I need to do it again.
So this evening I decide to take my chance. Claire is wearing a white skirt with pleats I've never seen before. It looks like a skirt a tennis player would wear, but she doesn't play tennis! It's short of course, it's looseness hinting at showing a little too much, but never does. She makes me hard as soon as I see her.
Laura is visiting her sister, and Ben is up in his room. I'm in the recliner watching TV when Claire comes down the stairs. I can't take my eyes off her perfect legs as she stands at the end of our kitchen island. I start at her bare feet, gazing up over her slim ankles, tracing her legs upwards as they slope wider at her calves, then narrow slightly at the knees. I keep going, following them up her sexy thighs, then I reach the hem line of her mini skirt, just an inch or two below the bottom of her ass.
When she comes over to the sofa, she sits down at the end closest to me, and lifts her legs up onto the cushions, tucking her feet in at the side under her ass with her legs to the side. I decide to just go for broke.
"So Claire, no gift for me for a few days now. What's up?" I say casually.
"Oh, yeah, I've just been really busy with school work. And I know you have a lot of work on, so I didn't want to bother you," she says, looking up from her book.
"I can do it for you now, if you like?" I say, but I'm starting to lose my confidence rapidly.
She smiles, leaves down her book, then reaches her hands up underneath her skirt to presumably take off her panties.
"No, I meant with them still on you," I say, my heart pounding. Jesus, I'm shaking.
She pauses with her hands up either side of her skirt. I can see to the very top of her outer thigh, her ass is buried in the sofa cushion.
"You sure Dad?" she says staring at me.
