I licked her lower lip and pulled my head away. “Monica, I’d like to be a gentleman about this, but there’s just no polite way to tell you how much I’m going to make you come tonight.”

She gasped, and I leaned in to nibble on her ear. The moans elicited from the sharp nip of my teeth on her lobe made my cock pulse.

She gasped again, but this time it wasn’t quite as sexy. She pushed me away from her and with an angry look over my shoulder asked, “Who the fuck is she?”

It took me a second to follow her gaze. When I did, I had to fight against the smile that tried to crawl across my lips. “Celia. I didn’t realize you’d be over tonight.”

I was as surprised as Monica to see my guest. Good thing I was excellent at winging it.

“Yeah,” Celia said, feigning embarrassment. “I guess I should have called first.” She was dressed only in a white fluffy towel, her hair wrapped in a second towel on top of her head. Even without the blush that would add to the authenticity of the moment, her speech and gestures appeared genuine.

A small burst of pride spread through me. I was impressed.

“Hudson,” Monica said, reminding me she was still there—like I could forget with my dick still throbbing in my jeans. “Who the fuck is she?”

“She’s…” I ran a hand through my hair and looked from one woman to the other, as if searching for an explanation.

“I’m Celia. A friend.” She tugged her towel higher over her lithe body. “I’m really sorry to interrupt your date. I’ll just go get dressed. Excuse me.” She apologized again as she ran to my bedroom.

“Hudson?”

I took a deep breath, removing the delight from my expression, before turning back to my date.

“She’s no one, Monica. An old friend. I didn’t know she’d be here.”

I moved back in to kiss her again, but she turned her face from mine. “Why is she here then? Does she have a key?”

Her suspicion delighted me. The entire setup of the scheme with Celia was to make my latest “girlfriend” doubt my fidelity. The experiment was meant to examine how long the subject—Monica—would stay with me if given repeated evidence that I may not be faithful. This was the first time in our relationship I’d given Monica any cause for doubt. We’d only been seeing each other for a week. I hadn’t even fucked her yet, an activity that had been on the evening’s agenda.

Until Celia had shown up, anyway. Now I was even more interested in getting it on with Monica, because, though I hadn’t expected my partner in crime to show up on this particular night, the fact that our game was proving fruitful made me very happy. Turned me on.

“Yes, she does have a key.” I did my best to sound like I was ashamed of this admission. “But only because she stays here now and then. When she’s fighting with her boyfriend. I didn’t know she’d be here.” The excuse was made up on the fly since I hadn’t been given a chance to prepare for this scenario.

Monica’s eyes widened. “She’s naked, Hudson!”

“Obviously she didn’t know I’d be here either.” I pulled her into my arms, and leaned my forehead against hers. “Come on. I’ll make her sleep on the sofa. Or we can get a hotel room.”

She melted into my body, her hands resting on my forearms. “I can’t believe I’m even considering this.”

“Monica, come on. Stay. I want you to stay.” This was easy to say because it wasn’t a lie. I’d been looking forward to burying myself inside her since the moment we’d picked her out for our experiment two weeks before. I kissed down the side of her face. “You know you want to stay too.”

“I do want to, but I don’t know.”

God, she was so close to being convinced. I rocked my pelvis into hers as I descended upon her mouth for a kiss she couldn’t say no to.

But before my lips met hers, she pulled away. “No. I can’t. Maybe this is innocent like you say, but I think it’s a cue to take a step back.”

I dropped my head with an only slightly exaggerated sigh. “Okay. I understand.” I grabbed my cock through my pants. “I’m crazy hard for you right now though. I’m going to be thinking about you all night.”

“Good. I’ll be thinking about you too.”

I escorted her out to the hall with a mixture of satisfaction and disappointment. On the one hand, she was going to present quite a challenge. That was a thrill I was looking forward to. On the other hand, she was leaving me with an ugly case of blue balls.

While we waited for the elevator, she turned to me with doe eyes. “Call me?”

“Tomorrow.” I planned to call her, but I already knew it wouldn’t be the next day. I’d make her sweat first. It would plant more seeds of doubt. “Goodnight.” I kissed her seductively, letting her know what she was missing out on.

After, I put her on the elevator. I kept her gaze locked with mine until the doors closed.

Then I went back to my apartment to deal with Celia.

She was lounging on the couch when I returned, sipping a bottle of Diet Coke. She was dressed now, or more accurately, no longer in a towel but in my bathrobe. Her hair was also no longer wrapped up, and I saw it wasn’t even wet. I suspected she had underwear on under the robe as well.

“How did it go?” she asked.

“Considering that I’m hard as stone, I’d say not very well.” I adjusted myself as I walked to the bar to make myself a drink.

“But she still wants to see you again?”

My back was to her, but I could tell she was eager for a progress report. It was understandable, though I imagined she’d listened to a good portion of it from the bedroom and already knew what had happened. Plus, it was fun to taunt her, so I delayed answering.

“You don’t seem to care that you cock-blocked me,” I said instead as I poured myself two fingers of Scotch, a recent discovery of mine.

“I don’t. I care about whether she’ll see you again.”

I turned toward her and took a sip of my drink. “She’ll see me again.”

Her entire face lit up, and she clenched her fists in a sign of victory.

While I was also feeling triumphant, there was a bone to pick. “But what the fuck, Celia? It wasn’t in the plan for you to be here tonight.”

Celia had shaped into being a great component of the experiments I conducted. She made variety possible, and I’d studied many new emotions and situations since she’d joined me nearly three years before. But as long as we’d played together, I’d always been the driver. I dictated the parameters of our research. I wrote the script. Of course, there was always a fair amount of ad-lib required, but as much as could be controlled was. And it was controlled by me.

This had been the first time Celia had surprised me in our ploy. It had been a good move, but I wasn’t ready to tell her that. Wasn’t ready to concede any of my authority.

“It was awesome improv though, wasn’t it?” She already knew she’d played well, whether I was ready to say so or not. My reprimand did nothing to shake her confident grin.

“I’ll admit no such thing.” I played smug as I joined her on the couch.

She swatted at my shoulder with the back of her hand. “Come on, it was perfect. I’m supposed to make her jealous and suspicious, and trust me, old friend naked in boyfriend’s apartment is the perfect way to do that.”

I rested an arm on the back of the sofa and studied her. “You’re extremely happy about this.”

“And you’re not?”

“Do I need to remind you of the cock-block?”

She threw her head back in frustration. “Oh, my God. You and your dick. Go whack off in the shower. You’ll be fine.” Then she curled her legs up underneath her and leaned toward me, her eyes sweet yet demanding. “Now admit that I did good.”

I hesitated. Finally, reluctantly, I conceded. “You did good.” I took another sip from my drink, letting the burn of it relax me and melt away the desire to hold onto the reins. “Actually, you did really good, Celia. Nice job.”

She wrinkled up her nose in glee as she soaked up my approval. Her pure joy somehow made it easier to continue the acknowledgment.

“You’re a lot more flexible with the experiments than you used to be,” I said. “You’ve come a long way.” There’d been quite a few in the early days that we’d barely survived. I’d never realized how naturally that scheming came to me. How hard it was to teach someone else. Yet, even with the difficulties, Celia had been born for it.

“I’d hope I’m better. We’ve been doing this now for…what? Three years?” She rolled her soda bottle in between her hands as she spoke, like a stick she was trying to rub into fire. “It’s about time I finally got a Hudson compliment.”

She was nervous, and I suddenly realized how much my acclaim meant to her. Was this the first time she’d received it?

I finished my Scotch and set the glass down on the coffee table, then peered at her with narrowed eyes. “I’ve complimented you before. Haven’t I?”

She shook her head. “I’m not complaining. I haven’t deserved it.”

I shrugged half-heartedly. She’d made mistakes, but overall I’d been pleased with her as a partner. More than pleased. I’d also been glad for her company.

She pursed her lips now, as if thinking. “Remember that couple in your building? The newlyweds?”

I nodded. How could I forget? They’d been our first experiment together.

Celia dropped her bottle into her lap and propped her elbow on the back of the couch, leaning her face onto her hand. “I’d been so nervous when I first approached him. Tim was his name. I was supposed to drop that bag of groceries, remember? And see if he’d help me with it. That was all there was to the first contact. You’d coached me and coached me. I swear I stood in that alcove of the lobby watching him flick through his mail for, I don’t know, an eternity before I had the guts to go out there. Then dropping my bag was easy because I was shaking so hard.”

“But he noticed you. He helped you with the groceries.”

“He brushed my hand even. On purpose, I think. And it was only our first meeting.” Her eyes narrowed as she lost herself in the memory. “He kept staring at my cleavage, and I remember how amazing it felt to have his attention, but at the same time, I thought he was a bit of a smarmy asshole.” She laughed. “Obviously, I got over the smarmy asshole part.”

I chuckled. “Obviously.”

It had been a great study. Celia had seduced Tim, the husband, while I’d worked my charm on the wife. My subject had resisted me, deeply devoted to her marriage, but Celia had succeeded in getting her subject in bed. Repeatedly. They’d had an all-out affair. Even when the wife had found out, she still refused to sleep with me, though she’d shown more than once that she was attracted. It had not been what I’d hypothesized. More surprising was that she forgave him for his infidelity.

I’d filed the entire experience as another attestation to the detriment of love. Why the fuck would any sane person forgive a spouse for that kind of gross unfaithfulness? It was weakness. Devotion made people stupid. There was no doubt in my mind.

“I still get nervous the first time we start any new game.” She leaned back into the corner of the couch and bent her legs up in front of her, her bare feet perching on the edge of my thigh. “And this is the first time I’ve felt comfortable changing things up without talking to you first.”

“Well, we don’t need to make that a habit now.” I pulled one of her feet into my hands and started rubbing it.

“We’ll see how it goes, I guess.”

I tried not to let that bother me. Things would morph just fine, I told myself. Whether I was in control or not.

We settled into silence. I continued my massage as I thought about how we’d both changed in the last years. Through our games, we’d become comfortable with more than just improvising. We’d found an ease in our relationship as well. We frequently staged kisses and embraces without any residual sexual tension. The undercurrent of emotional pull that had once existed between us had dissolved into something less fraught, less physical, yet intimate. We shared a rapport with each other that we had with no one else. We were…close. Friends. Partners.

I dropped her foot in my lap, ready to move to the other. The first brushed against my crotch. Celia’s forehead rose. “Is that your dick?”

“I told you I was hard.” It was actually a semi now, but certainly not flaccid, and the reminder of my pent-up lust for Monica had me stiffening again.

“Still?” She poked at my bulge with her toe and waggled her brows. “I can do something about that if you want.”