They had no fucking idea, I think to myself as I grab a heavier kettle bell. I exhale and lift it above my head. I feel my muscles straining against the weight of the iron and thin beads of sweat form on my forehead.

I was going to check in on Karen the other night, and maybe apologize for being so hot headed with Daniel. But as soon as I hit the top of the stairs, I heard them. At first I couldn't fucking believe it.

I mean seriously, what the fuck? He's our stepdad; why would she want to fuck him? But when I approached her door and looked in through the thin, open crack, it was obvious they were both enjoying it.

I'll admit. Seeing her get fucked like that made my cock spring to life. I couldn't shut it off. Believe me, I tried. So I had to go to my room and jerk off, and the whole time I kept thinking that it should've been my hands on her waist and tits. It should've been my cock buried in her pussy.

But you know what? It wasn’t just her. What was is that was turning me on so much watching them? Seeing a stepfather fuck his stepdaughter?

Fuck, lets be clearer. Seeing Daniel fuck Karen. Just thinking about seeing his cock – thick and veiny – as it pounded into her pussy is turning me on.

Why am I getting turned on by my stepdad?

I don’t know why it bothers me so much. Karen was flirting with me at the pool, but that doesn't mean she was going to let me fuck her. Maybe I misinterpreted the whole afternoon by the pool.

I came home to tell Daniel that maybe I was too hasty the other day, and that we should discuss what he needs for the business. I know he’s been working like crazy, first to pay Mom’s medical bills, which weren’t covered by the insurance, and then to put me through college. Also Clara’s rehab fees, and it helped put Karen through college too.

What I didn’t expect was to come home and find Karen fucking Daniel. After I jerked off, I went to my friend Bryan’s house, where I’ve been for the last three days. But Bryan’s gone on vacation today. He even begged me to join him. The temptation to go was so big. I’m in my final year of college and I thought that I would be relaxing and having a good time in Bali this summer. Not being summoned by Daniel to come home and then find him fucking Karen.

If it was another woman, it wouldn’t have bothered me. I can have any girl I want. They all come running; yet my mind’s stuck on Karen. She doesn’t even deserve it. One minute she’s all over me like a rash and then the next she’s with Daniel. Our stepfather. I wonder if that’s what she really came home for? To just fuck any guy that pays her attention.

Fuck knows.

The only thing that helps me when I’m in this mood is to work out. I came home today and luckily no one was around. So, I went down to the basement gym and decided that I would pump some iron. I’ll go for a jog in the morning. That’s pretty much my routine when it comes to working out. One day lifting weights and the next cardio. Then again, I’d rather be pumping Karen just like Daniel was doing the other night.

"Hey stranger," Karen purrs as she comes down the stairs. Fuck, so much for being alone. I can’t get my eyes off of her because she’s wearing hot pants that are really fucking tight around her ass and a sports bra.

Does she ever wear clothes? She should be wearing yoga pants and a shirt, not dressed as if she’s going to do a photoshoot for Playboy. Her boobs are struggling to stay in her sports bra. Why does she always wear tops that are too small for her?

Fuck, it must be to make sure that everyone notices that her breasts have increased by five sizes over the last year or so.

"So, you decided to come back?" she pouts as she comes in front of me. She’s taunting me with her body and those damn breasts!

What does she care, when she was only fucking Daniel the other night? I’m just about to say this when I realize that it’s none of my business. She’s not my girl. She’s only my stepsister, and—even worse—Daniel’s stepdaughter.

Why am I so fucking jealous?

She walks in front of me and bends down to pick up the weight. I’m shocked that she picks up a 20-pound weight with ease. Damn she’s strong! I’m tempted to find out how strong.

I can’t take this anymore. My cock is working overtime the same way it was the other day when I saw her in her bikini. She holds onto my arm and says, "Wait. Why won’t you talk to me? Did I do something wrong?"

Fucking Daniel for starters, but I’m keeping my lips firmly shut.

I don’t want her to know that it bothers me and I don’t even want her to know that I know the truth about them.

"I see that you’re happy to hand Daniel the money?" And your body. I skip that part. It suddenly dawns on me that she’s up to some game.

"The other day we were fine and now you’re acting like a jerk. The same way you used to when we lived in this house together. The things that you said to Daniel were out of line. Even you know that, right?"

"I don’t have to listen to this shit Karen. What, are you on a rebound or something?" She knows now that I caught them. Shit, I sound like a baby, throwing my toys. I watch as the recognition of it all dawns on her face.

"So… you know?" she asks.

"Yeah, but whatever. I guess it's your fucking business," I say.

Instead of saying another word, she carefully looks at me for a minute. It's as if she expected me to show more emotion, or say something else. But I honestly just don't even want to fucking talk about it. Then she moves closer to me, keeping her eyes on mine and I'm immediately taken back to our time in the pool.

"You work out a lot," she purrs as her fingers move from my arm to my chest.

"I play football. Of course I work out."

"Yes, but your abs are like a perfect six-pack… or is it an eight-pack?"

Why is she flirting with me now? I shake my head, "What about you and Daniel?"

"That’s none of your business."

I laugh, but there's also a serious undertone. "What if I want to make it my business?" I ask, holding her gaze.

She raises an eyebrow and asks, "Why are you so interested anyway?" I don’t answer and Karen takes a step towards me. "Do you want to fuck him or do you want to fuck me, brother?"

I don’t have an answer for her because I’ve been asking myself the same thing ever since that night.

Yeah, I’ve been thinking about Daniel, okay. But I didn’t put the word fuck into the equation until Karen mentioned it.

Just the thought of having sex with him while she stands there is driving my cock wild.

We stand in silence for a moment, and then the urge is too much. I can't hold back any longer. I am so fucking horny that my cock is gonna fucking break if I don’t let it out soon.

I lean in and kiss her with a hunger that takes over my body as I grab her and pin her against the wall, my lips crashing into hers.

She doesn’t even protest as I drive my mouth onto hers. I don’t care if Daniel comes down the stairs. My hands wander over her tight body and I pinch her ass. She starts to moan; she doesn’t even try and protest about the kiss. It’s as if she wants me as much as I want her. Maybe that’s why she ended up with Daniel because she’s just horny and needed to get off with someone.

Right now, I don’t care because I'm taking what I want.

I seize her firmly and lift her up against the wall so that we’re around the same height. She’s a little shorter than I am. Only five-foot-seven, but now she feels so small as she loops her arms and legs around me. Then she runs her fingers through my hair, raking her nails against my scalp in a way that sends an electric current down my arms.

"Colt," she whispers as she pulls me closer. Her shorts turn into small panties as my cock starts to push against them.

I start to growl as I rock back and forth, using the wall as leverage.

"Karen, you’re so fucking wet."

She mumbles, "This is what you do to me."

I don’t know what game she’s playing so I pull back and using one hand I wrap it around her chin. I make sure that her blue eyes see mine so that she knows exactly what she’s doing to me. I’m not just going to kiss her. I’m going to fuck her. She won’t even remember her name when I finish with her.

"When I saw you with Daniel. I wished that it was me."

She smiles, "Don’t wish. Take me. Show me. Please me," she says to me. Then with a seductive smile she leans forward and whispers in my ear. "Fuck your sister silly, brother."

I could pretend that it bothers me that only a few days ago, she was fucking my stepdad, but it doesn’t because I want her so bad. I’m not taking my erection into the bathroom and jerking off again. No, I’m going to come inside her and I press my cock deeper against her crotch, making sure that she knows what she’s up against.

"What are you waiting for?"

I start to bring my mouth to her neck while kissing and nibbling it in slow circles.

"You’re going to forget your name when I finish with you."

"Yes, please!" she says as I start to slowly put my finger inside her shorts. Fuck, she’s not even wearing panties, and she’s dripping wet.

Not for Daniel.

Just for me.