Alan slathered his dick up with the butter as best he could, and began the slow and tricky process of fitting it into Katherine’s anus. But it wasn’t nearly as difficult as entering Amy’s ass, especially since Katherine was completely relaxed and eager.

Susan recovered over the next couple of minutes, while he pushed into Katherine’s ass ever so slowly.

Out of the blue, he gave Katherine’s ass another hard whack.

Katherine exclaimed, "Finally! It’s about time!"

That comment puzzled him, so he asked, "’About time?’ What do you mean?"

"Remember last night, how you promised me that you’d give me a ’very thorough spanking’ tomorrow? Which means today, which means right now! Remember how you said you might even need to tie me up first?" That gave her an idea. "Hey, Mom! Can you get us some rope?"

Susan was overcome with another surge of lust. She didn’t cum again, but her mouth hung open in shock. Holy cow! A tied-up spanking is just about the greatest idea I’ve ever heard! If he’s going to do that to her, then he needs to do it to me. Fair’s fair, right? He can line us up side by side, with our arms tied behind our backs, completely and utterly helpless, and take turns fucking our faces and generally having his way with us!

Oh, what a great day this is going to be!

But to Susan’s dismay, and Katherine’s too, he said, "Not so fast, Sis. That sounds like something you’d enjoy, and you’re supposed to be getting punished right now. Besides, I was just joking around when I said that."

"DRAT!" Katherine complained. Stupid role-play! However, she realized she needed to play along. She quickly came up with what she hoped would be a good compromise. "Well, could you at least smack my ass a few more times while you squeeze Alan Junior in?"

"I suppose I can do that." He proceeded to give Katherine six more hard whacks over the next couple of minutes.

Katherine loved it. She particularly loved that she never knew when the next smack would be. It actually slowed up his progress into her ass because she clenched up her ass in anticipation of the next blow, but she figured it was more than worth it for the extra thrill and submissive joy.

Susan was beside herself with jubilation watching that. She only wished that it could have been a "proper" spanking instead.

Once Alan had managed the difficult task of fitting his bulbous cockhead inside his sister’s tight butt, he knew that the rest would be comparatively easy. He turned to Susan, who was sitting up and staring intently at his insertion. "Mom, please put your clothes back on, such as they are, and go back in the kitchen. I’m getting hungry, as I’m sure we all are. I’ll take care of Sis here."

From her vantage point, Susan could clearly see his erection entering Katherine’s asshole. That’s such an affront to God. Unnatural and sinful. So wrong! So wonderfully, deliciously wrong! She gasped lustily, "Yes, Son."

She spied her top on the floor where she’d discarded it a little while ago. Knowing that her son’s attention was still on her, she made a big production out of bending over to pick it up. She was particularly mindful to have her breasts dangle in an enticing manner.

As she did so, she thought, Dear Lord, I love my big tits so much! I used to be neutral about them, at best. They were a bother. But now, they’ve become a central part of my identity. All I have to do is bend over like this, and I can see a fire light up in Tiger’s eyes. Every single time, whether he’s erect or not. It’s such a rush! I’ll bet it’s making his cock throb and grow a little in Angel’s ass. This is what sex slaves do. We help each other out in little ways.

Once Susan finally finished putting her skimpy top back on, Alan turned his attention back to Katherine. He started stroking in and out, going a little bit deeper with each thrust.

Katherine was unabashedly enjoying what was happening, and that wasn’t just an act. (In fact, she was supposed to be disliking it, but she’d completely forgotten about that.) She was surprised that anal sex wasn’t the ordeal it had been the first time. It wasn’t really the physical act of being fucked in the ass that she was enjoying, as much as the whole milieu. She was extremely aroused before the insertion even began, which was a big plus. Also, she had loved their little role play, especially the reaction from Susan as she watched.

Sex and lust filled the room like a thick fog, and there was simply no way for anyone there not to feel aroused. She eagerly anticipated each new thrust.

Back in the kitchen, Susan had more or less straightened up her clothes, and was trying to focus on the pancake batter instead of the sounds of anal sex going on right behind her. She tried her best not to look across the counter to the dining room, and turned up the volume on her "Sex Slave Mix" CD to drown out the sounds of grunting and thrusting.

Unfortunately for her efforts to remain calm, the song that happened to be playing was "I’m Too Sexy" by Right Said Fred. Strictly speaking, the song didn’t fit the sex slave theme, but since Katherine had had trouble finding enough thematic songs to fill a CD, she added some just for their sexy aura, and this was one of them.

As the singer started to sing,

"I’m too sexy for my shirt,

too sexy for my shirt,

so sexy it hurts,"

Susan found herself starting to take her top off without even thinking about it, even tough she’d just put it back on. After a moment or two, she stopped herself, pulled her top back down, and tried to focus her attention on the pancake batter. Tiger just told me to put my clothes on and keep them on. He’s my master, which makes that an order. I’ll bet he said that so Angel will feel reassured that he has all his attention on her. Such a good son!

But when the singer started to sing about strutting around on the catwalk, she found herself strutting around the kitchen and taking her top off again, in striptease fashion.

Again she caught herself, but not until after she’d tossed her shirt over the kitchen counter. Oh dear me! I did it again! It’s just that I’m having so much sexy fun. How can I not at least get topless? But I have to obey my well-hung master!

She rushed to the CD player sitting on the counter near the sink and skipped to the next song, hoping that would help to calm her. But this song was "Sexy MF" by Prince (the uncensored version). Strictly speaking, it also didn’t have much to do with the CDs theme either, although it did contain the line "I’m with the blindfold, gagged and bound." But the chorus, with the repeated line "Come here baby, yeah, you sexy motherfucker," was her absolute favorite part of the whole CD.

As soon as the chorus came around, she couldn’t resist dancing. Sorry, Tiger! Sorry, Angel! I’m having too much fun! Just look at my children. Tiger is really giving it to her good! He’s punishing her, putting her in her place, and getting a great ass fuck at the same time. He’s so clever! It’s no wonder he’s tamed us all!

She whimpered and stared at the CD player helplessly as she continued to groove to the music. She muttered to herself, "There’s nothing I can do! Each song is better than the last. There’s no escaping Tiger’s sexy net!" (In her frazzled state, it didn’t occur to her to simply turn the CD player off.)

She turned to look back into the dining room, and she was hit with a memory so powerful that she actually staggered back a step or two. She suddenly vividly recalled a discussion she’d had with Suzanne over a month earlier, at a time when Suzanne was still attempting to break down her prudish defenses. Susan had become an enthusiastic cocksucker by then, but Suzanne was trying to convince her that anal sex was okay as well. This was when the two of them came up with the "bend over but don’t break" motto, a line that Susan still liked to think about and chuckle over from time to time.

As they had talked, Susan had brought up the possibility of Alan having anal sex with Katherine as well. This had led to Susan having a fantasy where she’d imagined Katherine naked and bent over the dining room table, with Alan relentlessly fucking his sister’s ass. In the fantasy, Susan had been in the kitchen, wearing nothing but her apron, and looking on like a proud mother while her daughter screamed in mingled agony and ecstasy as her well-hung son vigorously thrust in and out of Katherine’s butt.

The thought that had physically staggered her was that that previously outlandish fantasy was now a very real occurrence, taking place right in front of her. She could scarcely believe it. The only flaw was that she was wearing a miniskirt instead of an apron. Luckily, she kept a spare apron in one of the kitchen cabinets, so she quickly dropped her skirt and put that on instead.

Susan remembered how her little sex fantasy from what seemed like ages ago had concluded, with her getting down on her knees on the floor, her ass lifted up and spread by her very own hands and telling Alan as he continued to pump Katherine’s rear, "Now don’t forget about your mother!"

Without even really thinking about it, Susan’s hands reached back and gently cupped her sensitive ass globes, which were uncovered now that she’s switched to the erotic apron. She couldn’t stop her fingers from softly kneading her buttocks, and had to stifle a small cry of pleasure when she carefully pulled her ass open and felt a scintillating chill of cooler air touch her skin between her cheeks. She felt a thrill of yearning as her asshole fluttered with desire and need.

She was so overjoyed that she actually wiped a few tears of joy from her eyes. Everything is too perfect to be believed! Just look at them. LOOK at them! Even as he brutally plunders her ass, one can still feel the love between them. I’ve raised the best two kids in the whole world! It’s so right to see them like this, master and slave!

Giving up on her half-hearted effort to make pancakes, Susan wandered around the kitchen counter and sat on one of the tall stools. She sighed contentedly as she watched Alan continue to slowly plow Katherine’s ass. But what made her even happier was that, every now and then, he’d deliver a hard stinging slap to one of Katherine’s ass cheeks too. Each time he did that, Susan would jump in her chair a little bit, pretending that she was the one getting spanked.

Wow! Am I the luckiest mother in the world, or what? All my dreams are very literally coming true! I have no idea what the heck got into Angel there for a minute with her sassy and disobedient attitude, but Tiger’s taking care of it, one thrust at a time. God, he’s really slipping her the sausage, and she’s squealing like a stuck pig! Hee-hee! And I love that he’s starting to understand his slaves’ need to be regularly spanked, even if they are sister slaves... or big-titted mommy slaves! Hee-hee! She started out all rebellious, but just look at her now - she’s totally tamed and loving it!

She had a "Eureka!" moment. Hey! All Angel had to do was talk sassy and cover her body with too many clothes, and bam! Ass attack! Gaawwwd, I NEED that dick in me!

It was only a minute or so after she’d come to that realization when Katherine had a loud and satisfying orgasm. She watched as Alan pulled out of Katherine to go sit on the love seat in order to rest.

Katherine remained bent over the dining room table, panting for breath as her body quivered and twitched.

However, just before sitting down in the love seat, he changed his mind and went to the kitchen to grab a handi-wipe so that he could clean himself off first. His attention had been entirely on Katherine during the ass fuck, but now that he was passing through the kitchen, he gave his mother a good look over. He merely smiled at her while he wiped his erection clean.

Susan struck a sexy and submissive pose, with her arms pinned behind her back. "Son! Color me impressed! You really gave it to her good!"

He still just smiled in return. But once he had the handi-wipe in the trash, he walked up to her and swept her in his arms. "How you doing, Mom?" He gave her a big kiss on the lips that left her breathless.

Yet before the kiss was over, she had both of her hands on his boner and all ten fingers pumped up and down. She finally replied, "I’m doing great! Even better, now that you’re here!"

He looked down at her sliding fingers. "Yeah, well, sorry, but I’m just passing through. I’m gonna go crash on the love seat for a while." He disengaged.

He started to walk away, but then he turned around and gave her a solid whack on one ass cheek and then the other. He resumed walking away, saying, "That’s for disobeying me and taking your top off." But he winked at the same time, showing he wasn’t upset at all.

Susan was in awe, her entire body trembling with lusty desire. BEST. DAY. EVER! And we haven’t even had breakfast yet!