As I stepped into the shower, I felt a strange sensation that something was wrong. Both Jennifer and Mackenzie were acting weird, and I wanted to find out what was going on. Neither one of them had used the bathroom while I was in the bedroom, and I could usually tell such things at a glance.
Not wanting to seem like I was trying to be the "fun police," I turned off the shower to give them both a warning, and then I stepped out, wrapped my towel around me, and opened the door. I was surprised to see Mackenzie standing right there, right outside the door.
"Oh, hey," I said, glancing to my right toward the kitchen. "Uh, I think I forgot uh...something in my bedroom."
"Uh-huh," Mackenzie said, giving me a once-over look. "You weren't coming out to try and spy on us?"
"Spy on you?" I asked. "No. Why would I spy on you?"
"To try and catch us switching again," Mackenzie said.
"No. No, I...have to grab something," I said.
"Okay, well, Jennifer is putting in a load of laundry," Mackenzie said as if ratting her out.
"Why? She knows it's going to use the hot water," I said.
"Maybe that's why she's doing it. So you won't use all the hot water."
"Shit," I said, turning around and heading back into the bathroom.
"What about what you left in your room?" Mackenzie asked.
"I... I'll get it when I come out," I said, and I closed the door and pushed the little button on the handle.
I dropped my towel, stepped into the shower, yanked the shower curtain closed and turned on the water, scalding hot for just a second to get it flowing, and then I turned it down until it was tolerable.
I grabbed the soap and was about to start lathering up when I felt the air pressure in the bathroom change, and the shower curtain fluttered.
"Hello?" I asked, thinking, remembering absolutely that I had locked the door.
"Hey," Mackenzie replied and I heard the door click and then the button was pressed, locking the door.
"Hey," I said, lowering my voice. "What are you doing in here? How did you get in?"
"You left the door unlocked," she said, and then she added, "I have to use the potty."
"Oh. Okay," I said, standing there like a little girl, the soap clutched in my hands, held tight to my hairy chest. I didn't know what to do other than wait for her to leave.
"Can you help me?" Mackenzie asked after a moment. "I think I'm stuck."
"Stuck?"
"Yeah. It's stuck."
"What's stuck?"
"Just come out here and help me," she giggled.
I set the soap back in the wall dish and slowly pulled back the curtain, leaving the shower running to mask any noise I was making, and what I saw, both shocked and surprised me.
Mackenzie was kneeling on the toilet, her hands on the back of it, her knees on the seat, and her bare ass in the air. She was looking back over her shoulder at me, a huge smile on her face, and when she reached back and grabbed hold of the little blue gem that was where her butt hole should have been, I knew what she was talking about. "Can you help me get it out?"
I grinned and contained my laughter as I stepped out of the shower as quietly as I could. My cock swung back and forth awkwardly, growing harder by the moment. "Where did you get this?" I asked, coming up to her behind and placing a hand on her right cheek.
"It's mine," she said. "I have a few. Different colors, different designs. I have one that's a rose," she said as if proud of her possession. My cock throbbed, jumping slightly.
"So, what do I do? Just grab hold of it and yank?"
"Uh, no. Not unless you wanna break my butt hole," she said warningly.
"Uh, nah. Not today," I said, my cock remembering just how fantastic her ass felt.
"Just grab hold of it and pull it out slowly."
I reached down and grabbed hold of the gem and found it set into a heavy metal stud. I slowly slipped my fingers around it and gently started pulling it out. A good inch of solid metal rod came out before Mackenzie's asshole started to expand, the puckered ring stretching until the skin was a glossy pink ringed by soft brown skin. I thought I heard her moan as the thing got bigger and bigger until, at last, the spade-shaped body of the plug popped out of her ass.
"There ya go," I said, holding it out for her to take.
"Aren't you going to replace it?" She asked.
"Replace it? With what?" I asked, thinking she had a different one to put in.
Mackenzie turned her face back to me and gave me a silly smile. "Your cock. You only take a butt plug out when you're ready to fuck that ass," she whispered. "Come on, before Jennifer gets done folding laundry."
I didn't need to be told twice, and as I pulled her ass down to line up with my cock, her asshole relaxed and opened up as if waiting for my entrance. I put the tip against her ring, and she pushed back, taking half my cock into her ass in one smooth motion.
"Come on," she urged, moving her hips forward and then back. "Give it to me. I want it all."
"Mmmm," I moaned, grabbing her hips and pulling her back, pressing my cock in deeper. The head of my cock slid in, and then, there was a bit of a ridge, and then, as I pushed further, my cock pushed through and slid all the way in until my balls were tight against her ass.
"Oh fuck," I heard Mackenzie moan, and she reached back between her legs and began rubbing her pussy with a vigorous fury. "Come on. Fuck me, big daddy," she moaned. "Fuck my ass. Fuck it. Give it to me."
I pulled my cock out halfway and slid it back in as deep as it would go. Her asshole was hot and moist, not slick like her pussy, but tighter, more grippy, but she was talking like she wanted me to fuck her for all she was worth. I gave her a few more strokes, nice, deep, long strokes, feeding her every inch of my cock that I could.
"God damn," she moaned, and then she looked back at me, a lustful, wanting look in those pretty little eyes. "Fuck my ass, hard. Come on," she said, turning back to face the wall behind the toilet. "Give me that cum."
I slid my cock all the way in and then jerked it halfway out before plunging it all the way back in. "Oh yeah!" She yelped, and then she bit her wrist and whimpered as I continued doing that same thing over and over again. "Oh god," she whispered, and then her hand was on her pussy again. "Fuck it, fuck, fuck, fuck it, baby, fuck it so good. Make me cum. Make my fucking ass come all over your cock."
My cock couldn't hold back with talk like that. It swelled, throbbed, convulsed, and then I felt the tell-tale tingling sensation as my sperm was loaded from my balls into my shaft, racing toward the tip.
"Oh fuck," I groaned, and I pulled her hips back, burying my cock as deep as it would go. Cum ripped out of me, flooding the depths of her anal cavity, shooting hot semen deeper than her womb. Her asshole clenched around me, and she kept moving, pulling her hips forward, sucking the sperm out of my shaft, and then she would loosen and push back, taking me in and pushing my cum load deep up inside of her. She repeated the process until my cock went completely limp and slid out of her asshole to hang lifeless between her legs.
"Gimme," she said then, reaching back and holding a hand out.
Absently, I put the butt plug into her waiting hand, and she reached back, pressed the spade against her asshole, and I watched as it opened, swallowing the thing whole. Only the little gem stood visible.
"Thank you for the fill-up," She said, standing up and bending down to retrieve her clothing. "Big Daddy."
"You like calling me that, don't you," I asked, watching her slide the skin-tight pants back up her legs.
"Uh-huh," she said, smiling at me. "That's what you are. Big, and daddy."
"You uh, you forgot your panties," I said; nothing she wasn't wearing.
"Oh, I don't wear panties," Mackenzie said innocently.
"Then why did we buy all those panties today?"
"They're Jennifer's," Mackenzie said, struggling to pull the jeans up over her wide hips. "Uh, think I can get some help?"