Her solution

The light clicked on.

Mia was lying on our bed, propped up on one elbow, completely at ease. She was wearing a parody of a school uniform — a white blouse straining at the buttons, a green pleated skirt so short it barely qualified as clothing, and a striped tie knotted loosely at her throat. Her free hand played idly with the hem of the skirt, lifting it a centimeter, letting it fall, lifting it again. She smirked at me like she'd been waiting all afternoon for the show to start.

I turned, wordless, to Emily.

She'd let the dressing gown fall from her shoulders and pool on the floor behind her. Underneath, she wore the same outfit as Mia, but somehow it fit her entirely differently. The white shirt was pulled tight across her chest, the buttons stretched, her cleavage pushed up high and full. Her nipples pressed clear and sharp through the fabric, two obvious points that made my mouth go dry. The tie hung loose around her neck and disappeared down between the cleft of her breasts. Her skirt was little more than a frilled belt, green with yellow stripes, covering the necessary parts. For now.

"Oh sir," she said, eyes wide, one hand toying with the knot of her tie, the other pulling gently at her bottom lip. "I'm sorry we've been naughty. Perhaps you need to punish us?"

She walked a slow circle around me, her skirt swishing, then hooked her fingers into the waistband of my jeans and tugged me toward the bed. Mia slid over to make room, and Emily arranged me between them both, flat on my back. The ceiling spun slightly. I hadn't had a drop to drink and I still felt drunk.

"We've been very bad girls," Mia said, that smirk widening.

Emily's hand found my crotch and began to massage me through the denim. Then her lips were on mine, soft at first, an easy, familiar pressure. Then harder, hungrier, her tongue sliding in, tracing my teeth, exploring my mouth like she was rediscovering it. I closed my eyes and let her in, tasting her, forgetting everything.

More hands joined hers. Fingers at my button. The zipper came down with a rasp, and cool air hit my skin for a second before warm, wet heat swallowed me whole.

I gasped and broke the kiss, lifting my head to look down my own body. Mia had shuffled between my legs and was already taking me deep, the whole of me disappearing into her throat with each unhurried bob. My head dropped back against the pillow. My eyes closed again.

When I opened them, Emily was leaning over me, and the innocent, wide-eyed act was gone. The smirk on her face was pure co-conspirator.

"We've been very bad, sir," she whispered. "But I promise we'll be better. We'll do anything to make it up to you."

She worked the buttons of her shirt open one by one, then shrugged it off and let it fall away.

Beneath it was a white corset, stiff boned, with a built-in shelf that pushed her bare breasts up high and proud. Her nipples were hard little pebbles, jutting out at me, flushed dark. Without the tight shirt imprisoning them in place, her breasts settled, heavy and natural, swaying with her breathing. Her tie remained, now hanging loose.

She climbed up my body and smothered my face between her breasts, my world narrowed to skin and the smell of her perfume. She fed me one nipple, then the other, and I sucked at each like it was the only thing keeping me alive. Her breath caught and quickened above me, a small sharp inhalation for every pull of my mouth.

She pulled back with a gasp. Her tie hung loose now, her breasts completely free. She caught the tie in her fingers again, twisting it, tugging it, drawing my eye down its length.

"You know, sir," she said, "we know we need discipline. We understand if you need to get a little… rough with us."

She gave the tie a sharp pull to make the point, then bent low and pressed her lips to my neck. She kissed her way down to my Collarbone, a slow, deliberate descent.

Mia chose that moment to take me to the root again, and there was a swallow, a ripple of muscle travelling the whole length of me that made my hips jerk off the mattress. She drew back just as Emily arrived alongside her, and then both of their mouths were on me at once, kissing and licking along my shaft, tongues meeting and sliding past each other.

In the brief space that opened up, they worked my jeans down my legs and threw them off the bed. Some remnant of my brain came back online and I sat up enough to yank my t-shirt over my head, and then it was gone again, because they'd resumed and there was nothing in the world but what their mouths were doing.

Emily climbed on top of me and slid herself along the length of my erection, coating me in hot wetness. I could tell immediately there was nothing under that skirt. Nothing at all. Mia shifted behind her and unclasped the skirt from her waist, pulling it away and tossing it off the bed.

Every rock of Emily's hips brought her entrance closer to the tip of me, close, closer, then away. Mia's hands returned, cupping Emily's breasts, her thumbs working the nipples in slow circles, then sliding down her stomach, down her back, unhooking the corset one steel hook at a time. The boning loosened, the fabric gaped, and as the corset came away Emily rolled her hips back — and her entrance caught, and I slid inside her all at once.

"Fuuuuuuuuuck," she said. Her eyes closed. Her head fell back.

Everything went quiet and perfect. Just Emily around me, warm and tight, her hands braced on my chest, her hair falling forward, both of us breathing the same rhythm. For that handful of seconds it was only us. It was the two of us, the way it was supposed to be.

Then a shadow fell over my face.

"Aren't you going to discipline me too, sir?" Mia asked, sweet as poison, and swung her leg over my head and lowered her sex onto my mouth.

Her hand knotted in my hair and she began to grind, unhurried and completely in control, dragging herself across my face. I stuck out my tongue and found her clit by feel, but she was setting the pace, the pressure, the angle. All I could do was keep up. I breathed through my nose whenever she gave me the chance and tried not to panic when she didn't. Whatever she'd called me, there was no doubt in that moment who was in charge.

She lifted off. I gulped cold air. Then she was back, turning herself around to face Emily, and this time she angled herself forward and ground her clit against my chin, my nose buried in the cleft of her ass, her thighs clamping either side of my head. Above me I heard wet, breathy sounds and caught flashes of them: Mia bent forward over Emily, kissing her deeply, one hand pinching Emily's nipple hard and pulling her into it.

Emily squealed. Her whole body clenched, a tight squeeze rippling down the length of me, and I went over the edge, spilling into her with a groan muffled against Mia's skin.

Mia kept kissing her, but softer, slower. "Mmmm," she murmured against Emily's mouth. "Good little pet."

She climbed off me. I lay there, chest heaving, my ears ringing.

"You," Mia said, looking at me, and the sweetness in her voice had a hard edge. "Sit up."

Emily climbed off and I pushed myself up against the pillows. I didn't see any reason to argue.

"Pet," Mia said, much more gently now, gesturing down at my crotch. "Present, and clean your mess."

Without a word, Emily dropped onto all fours and took me back into her mouth.

She was gentle about it, suckling softly, her tongue moving in slow circles around the head, and in that oversensitive afterglow it made my whole body shiver. I let my head fall back and steadied my breathing.

Mia appeared behind Emily again, fitting the short end of a pink, strapless strap-on dildo into her pussy. The long, curved end jutting out ahead, thicker and longer than I was. Emily paused and tensed.

"My turn, little pet," Mia said, and drove it into her causing Emily to jerk forward with the impact, her eyes flying wide. My cock slipped out of her mouth for a moment before she caught herself and dipped her head back down, taking me in again while she absorbed the thrust.

Then she found the rhythm: forward and back, Mia's hips driving her onto me and her pushing back deeper. Her eyes closed. A long, low moan hummed out of her throat, straight down the length of my shaft, and I felt myself begin to stir again against her tongue.

SLAP.

Mia's hand cracked across Emily's right cheek. Emily moaned louder but didn't break rhythm, didn't stop, didn't slow.

SLAP.

The left this time, harder.

Mia reached forward, grasping up Emily's tie and wound it around her fist, hauling back on it so Emily's spine arched, her head coming up, her mouth losing me again for a half second before she puled back down. The spanking went on, each one landing with a meaty crack, each one dragging a moan out of Emily that she kept swallowing around me.

She came. Her whole body seized and shuddered, a broken wail escaping her. Mia didn't stop. Emily shook through it, kept rocking, and came again a minute later, and then a third time, whimpering, tears on her cheeks, still not stopping.

By then I was fully hard in her mouth again. Mia drove deep, held, ground her hips, and came with a groan, her fist still knotted in Emily's tie.

And it was over.

Mia eased out and set the toy aside, and Emily sagged, stopping her suckling, slumping sideways onto the mattress in a boneless heap, her cheek on the duvet, breathing in ragged, hitching gulps.

Mia got up and dressed without ceremony. Knickers, blouse, skirt, tie. She didn't rush it, and I watched her in silence, my heart still slamming, my dick standing up out of my lap as stiff as if none of it had happened yet. I couldn't seem to make myself cover it.

Once she was fully put together, Emily had come back to herself enough to push up onto her elbows. Mia bent and kissed her full on the lips, lingering, one hand stroking her hair.

"Can't wait for next time," Mia said.

She straightened, gave me a wink, and blew me a kiss from the doorway.

"Nice to meet you. I'll let myself out."

Her footsteps sound through the apartment. Then the front door clicked twice, a little further away.

Emily sat up, and the moment Mia left, all the hardness went out of the room. She crawled up the bed and folded herself against my side, her head on my shoulder, her arm across my chest.

"Thank you for understanding," she said softly, and her voice was pure Emily again, warm and a little shy. "I think this will be good for us."

She pressed a kiss to my collarbone, then rolled away and stood up, stretching, entirely unselfconscious under the lamplight.

"I'm going for a shower," she said, and padded away into the bathroom, the little metal plug once again between her ass cheeks, glinting in the light. The door closed. The water started running.

I didn't move. My dick was still standing straight up, absurd and insistent, unbearably hard. My breathing short and shallow, like I'd been sprinting and hadn't stopped yet.

What exactly had I just agreed to?

And what exactly was going on between my girlfriend and Mia?