Give them a chance to please you.

"Stacey, get the lube," you said. She dashed to your bedroom in an instant to grab it, "And your buttplug," you called after her.

"Yes master!" she shouted back.

Krissi's expression of dismay grew starker.

"Please, don't do this to me," she said in a timid voice.

"Do you really mean that?" you asked as you stripped out of your clothes. Your cock was standing rock hard, dripping a little pre-cum. The whole show Stacey had put on Riding Krissi's face, followed by her sculpting of that beautiful ass, had really worked you up. And you hadn't cum for, oh, nearly a half hour! Enough time to recover several times over with your new stamina.

"Because I think the way you're looking at my cock you'd gladly suck or fuck me anyway I order you to get your cum fix. I think you're going to be begging me to use you as my cumdump soon. You're even drooling already."

It was true, Krissi's mouth had started watering looking at your cock. She wiped her cheek then looked away in shame.

"Got it, Master!" Stacey exclaimed, brandishing a bottle of lube. She glanced meaningfully at Krissi, then at you. She was giddy now that you'd promised her sweet release.

You simply nodded.

"Face down, ass up, whore!" Stacey barked at Krissi, who promptly obeyed. She wasted no time squeezing a glob of lube into her hand and coating the buttplug. She pulled down Krissi's panties, revealing her asshole and her cock beneath the skirt. Then she poised the buttplug right over that exposed asshole at the center of that luscious, feminine ass. Krissi let out a yelp as the tip of the plug pushed into her puckered hole. Even with the lube moaned in surprise and discomfort.

"Maybe you'll get off from this you little freak, if you're lucky," Stacey said. She had the plug halfway in now. She was slowly sliding it in and out, a little deeper each time. It wasn't a large toy at all, but Krissi moaned and whined as if it were stretching her beyond her limits.

"Please stop, I can't handle it! It hurts," Krissi's squeals were, you noted with wry amusement, naturally high and girlish. Stacey just picked up her pace. She started to talk more.

"You're getting your first real taste of your new life now. You're a toy and nothing more to us. When we want to use your ass, we use your ass. When we want to use your mouth, we use your mouth. When we want to use your cock we'll use your cock. Don't hold your breath on that one though!" she cackled, "We control your mind and we control your body. If I want to make you the biggest anal slut in the world cumming buckets the second your asshole gets teased, I can. If I want to take your cock away, or make it constantly spurt out jizz without you ever orgasming, or make it so long you can suck it yourself, I can."

Krissi didn't seem to be getting much pleasure out of it at first, but then slowly you noticed her cock hardening, and even a little precum dripping out. Her protests slowed.

She's sensitive to anal stimulation in a way the average person isn't, apparently, or just so worked up that anything will do the job. But either way her cock is soon rock hard and leaking ample drops of precum on the floor. She dares to scoop some up with her fingers and lick it, and when neither of you stop her she keeps doing it. Stacey gets more and more rough with the buttplug, but pleasure far outweights pain for Krissi now.

"Oh make me cum mistress! I'm so close, so close!", her face is flushed, she's on the edge.

You gesture to Stacey to move aside, and position yourself on your knees behind Krissi. Krissi realizes in a second what's going on. Reticence flickers across her face, only to quickly be replaced by resolve.

"Please fuck me master!"