It was mid-afternoon when Mark saw the new notification on his phone from his credit card app. It was a card he and Lisa kept for emergencies so charges like this nearly $500 purchase at a local clothing boutique were unexpected. He figured he knew the circumstances and would straighten it out later at home.

Mark arrived home with a bag of Chinese take-out - their Friday night routine. Lisa and her sister, Jayne, were already on their second glass of wine and Mark poured himself one and set-out the contents of the bag. They ate and talked about their respective days. Mark was inwardly amused that the topic of the new clothes did not arise. He had seen the conspicuously posh bags in the foyer.

As he was clearing the dishes, he nonchalantly queried, “So, I noticed a rather large charge on the emergency card today. What was the emergency?”

He saw Lisa pause, realizing his demeanor shift. “Jayne has two interviews next week and needed a few dressier outfits. She’ll pay us back once she gets a job,” Lisa replied trying to emphasize the positives. Jayne had worked in the IT department of a local start-up. It had folded two months ago and, to save money, she had moved in with Lisa and Mark until she found a new gig. Usually, her presence had not been disruptive or unwelcome, but there had been a few friction points that had riled Mark. During the first week of her stay she had driven home tipsy and Mark had decreed - with Lisa’s agreement - that such behavior would not be tolerated and any future missteps would be met with harsh consequences.

Mark countered, “It’s not that you bought her clothes. I’d be willing to give them to her without expecting repayment. I’m just irritated that you used the card we both agreed would be reserved for actual emergencies.”

Jayne realized that Mark was heated about this and tried to defuse the situation. “It’s kinda my fault,” she offered. “Earlier I had bought some girl stuff online with her usual card and I hadn’t returned it when we left for the shops so she only had the emergency card in her wallet.”

Mark did not bother to discover what exactly ‘girl stuff’ was and suggested, “Perhaps if you feel partly responsible, you should receive a portion of the consequences.” He unbuckled his belt and Jayne realized the mistake of admitting fault in the fiasco. She sighed and slid down her yoga pants and panties before draping herself over the high, padded arm of the sofa. It was not an unfamiliar position for her and she knew that when Mark unbuckled his belt like that, the best response was to assume this position and accept the punishment she had coming. After that first warning about drinking and driving, it had happened twice more and each time he had thoroughly lashed her bare bottom with his belt. On a few other occasions she had stayed out all night and failed to apprise them that she was not coming home or where she was staying over. In those instances, Lisa had scolded her younger sister about basic personal safety, after which Mark had emphasized the message with a few dozen strokes of that awful belt.

Mark now doubled the belt in his right hand and tapped it against his sister-in-law’s bare bottom. He laid the first, fierce stroke across the crest of her round cheeks and she squealed in response. He worked the next five strokes of belt expertly from there down to the tops of her thighs, then began at the top again for a second pass.

When Jayne was sobbing and rubbing her bottom, her sister stood to take her own dose. Lisa settled onto the couch and waited to absorb the sharp bite of the leather. The one consolation was that she knew how aroused it made Mark and the vigorous sex that was sure to follow later. She gritted her teeth and tried to be stoic in her reaction but at the end, tears were leaking from eyes, as well.

After Mark had strapped the two women, he rethreaded his belt. A few minutes they were convened on that same couch, watching a movie and snacking on popcorn. Mark was a bit amused at how the two frequently shifted to find a posture that put less pressure on their well-heated bottoms.

Later, Jayne was laying in bed on her side. Her left hand traced the welts on her bottom while her right fingered herself. She listened to the sounds from the master bedroom, wondering if they realized how well the sound carried through the ductwork. At first she only heard muffled voices, but then about a full minute of sharp whacks that she figured where hairbrush on bare butt. There was a brief pause and then another sustained minute of swats. She wondered about the state of her sisters bottom after a dozen belt strokes and now nearly two minutes of hard hairbrush swats. Those thoughts were distracted by the clear sounds of energetic coitus - bouncing of the bed, moans, a local orgasmic vocalization from Lisa and then a low moan she imagined was Mark cumming. The images made her all the more wet and she herself soon climaxed.

After the movie ended, Mark spent a few minutes cleaning up the kitchen and making sure the doors were locked and lights were off. When he entered the bedroom to find Lisa sitting naked on the bed holding one of their favorite spanking tools - a wooden hairbrush they had bought at an estate sale. “So what do you have in mind,” he asked. “I figured you were due a bit more - with that - for the whole credit card thing.”

“Perhaps,” Lisa countered, “But I noticed the bulge in your pants while strapping my sister and I think there needs to be some consequences for becoming aroused by spanking her butt.”

“Fair enough,” Mark admitted and moved to his wife’s right side. She undid the belt that had left deep welts on her own butt and tugged his slacks and boxers down. Once he was across her knee, she began to paddle his taut cheeks until they were bright red. When he stood he was hard and she slipped to her knees and took him in her mouth. He felt himself rising towards apex and pulled away. “Save that for a bit,” he suggested and coaxed her over his lap. He paddled her already colorful bottom until it glowed like two bright pink orbs. He prompted her to kneel on the bed and entered her from behind. It was a position that they both enjoyed and she moaned loudly. He wondered how much of their bedroom escapades were audible to Jayne but that only made him thrust more vigorously. He felt Lisa tense and then pulled out to release a generous series of sticky, hot streams onto Lisa’s red bottom. The two flopped onto the bed, pleasantly exhausted. “I do so like it when you misbehave,” Mark whispered.