It had been about three weeks since Angie put Rebecca in charge of me. Most of the marks on my bottom had faded, but the cain marks were still faintly visible.

Rebecca had been leaving a list of chores for me on the kitchen table daily. I completed every task promptly and efficiently, less out of fear of whatever punishment Rebecca might prescribe than fear of incurring Angie's wrath again.

Rebecca was physically smaller than me and did not spank nearly as hard as Angie, who was taller than me by at least six inches and had a much more formidable presence. It was very clear who the dominant one was in their relationship. Also, Angie had given me an ultimatum: obey and respect Rebecca or find another place to live. So I was on my best behavior, doing whatever chores I was assigned without complaint.

Still, there was part of me that wanted to test the limits, to neglect a chore or two on purpose, or to do it badly enough that Rebecca would have to punish me, just to see what she would do. So far, I had avoided acting on this impulse. I was being a good boy.

One night I was sitting on the couch playing a video game when Rebecca and Angie came home from wherever they had been that evening, embroiled in an argument. I heard them outside before they even got to the door, Rebecca's higher-pitched whine a stark contrast to Angie's stern, lower voice.

"It's not fair," Rebecca said as she entered the apartment.

"I don't care if you think it's fair," Angie said, coming in behind her. "It's how it's going to be. And don't think that I forgot about what I said was going to happen once we got home."

Angie walked straight to their bedroom without acknowledging me, while Rebecca stood in the living room and stomped her foot, defiantly tossing her hair over her shoulder with a bratty huff.

I didn't need to know the context of their argument to understand what was going on. Rebecca looked at me and her expression said that she knew that I knew.

"Get in here, young lady," Angie said from the bedroom.

Rebecca gave me a cocky half-smile and a little shrug before turning and walking sheepishly to their room, closing and locking the door behind her.

I heard their muffled voices continue to argue for about another minute, Rebecca's getting increasingly more whiny and Angie's becoming more direct and authoritative. I wanted to hear what they were saying, but I was afraid they would see my shadow under the door if I stood there listening. I certainly did not want to get in the middle of this.

The bathroom shares a wall with their bedroom, so I decided that would be a safe enough place to eavesdrop. As I put my ear to the bathroom wall I felt an erection forming in my pants as a delicious sense of naughtiness washed over me.

They were no longer arguing now. The spanking had begun. The smacks were loud and rapid with Angie's lecturing voice punctuating every other one. I still couldn't make out exactly what she was saying, but it sounded like Rebecca had failed to take care of some kind of task that Angie had assigned her and Angie was displeased with Rebecca's attitude about it.

I could tell by the sound that Rebecca was being spanked on her bare bottom. I had known this was a practice between them for a while, having overheard them on a couple occasions. Also, having been over Angie's lap with my pants down myself just three weeks earlier, I knew exactly how those spanks felt. I replayed that night in my head often, sometimes jerking off while looking at my own marked butt in the mirror. Now, as I visualized Rebecca draped over Angie's lap, her naked bottom turning a brighter pink with every smack, I couldn't contain myself anymore. I unzipped my pants and pulled my penis out. I squirted some of Rebecca's body lotion into my hand and began stroking.

The spanking continued, interspersed with tiny yelps from Rebecca.

I unbuckled my belt and pulled my pants and underwear down to my knees.

After another minute or so the spanking stopped and I could hear Angie ordering Rebecca to put her nose against the wall. I pictured Rebecca standing there, just on the other side of the wall, her pants and panties around her ankles and her glowing red backside on full display.

I put one hand against the wall, wondering if she could sense my presence, both of us standing just a few inches apart, both of us naked from the waist down.

I began masturbating even more furiously at the thought, and my pleasure was so intense as I blew my load into the sink that I did not notice their bedroom door opening or Angie's footsteps approaching the bathroom door that I had failed to close all the way behind me.

"Are you having fun?" she said.

I turned to see her standing in the doorway, looking me up and down. My dick was still in my hand dripping with cum. I made no effort to pull my pants up before launching into a stuttering apology. I had been caught masturbating to the sound of Rebecca being punished, there was no possibility of denying that fact.

"I - I'm sorry," I said. "I just...I mean...um... I'm sorry, I'm sorry."

"Yeah," Angie said, "you're sorry alright. Clean up after yourself right now. And maybe you should stay in your own room for the rest of the night."

"Y - yes, ma'am," I said, "Are you going to tell Rebecca?"

"Oh yeah," Angie said, "she's definitely going to hear about this."

With that, Angie turned and walked away, leaving me to put myself back together.

Back in my room, I could still make out the muffled sounds of Rebecca being punished. It sounded like Angie had moved on to the belt. A little while later this was replaced by moaning from both of them as they made love. I lay there in my bed, dressed now only in my underwear, gently rubbing my still throbbing dick while wondering in my post-orgasm clarity what kind of consequences were in store for me and how long I was going to have to wait to find out.