That's a bold assumption that you're going to make her cum

"I've got an idea." Grace says.

You watch her walk off and grab a chair which she places in front of you. Then she removes the strap-on, which makes you raise an eyebrow. Next, she removes her dildo from the harness, before placing its suction cup on the chair. It stands at attention, ready to please its owner. You watch as Grace hovers over her 'cock', and grips its shaft.

Looking over her shoulder to you, Grace says "Ready for a show?"

"Yes Mistress Grace." You say.

"Mhmm, good boy."

Grace begins rubbing the lips of her entrance against the tip of the toy, as Adela squats down behind you. One of her arms wraps around your chest, as the other reaches for your throbbing erection. Grace then begins to lower herself down the dildo's length, gasping as she does so. You watch as more and more of its shaft sinks inside of Grace.

Adela begins stroking your cock before leaning into your ear and whispering "I'd peg your ass, but you'd enjoy it too much, Pet."

You offer your Queen no reply as you find yourself near hypnotized by everything Grace is doing. From the way she's moaning in pleasure, to how that perfect ass bounces up and down her thick, long dildo.

"Beautiful, isn't it?" Adela says.

This time you manage a nod as you continue to lose yourself further in your trance.

"How's that toy Grace?"

"Ohh it's so fucking good!" Grace cries.

Your Queen then leans into your ear once more and whispers "Look at you. You're practically drooling. Bet you wish that was your dick, don't ya Pet?"

"Yes my Queen."

"Say it louder, so she can hear."

"I wish I was riding your cock Grace."

Adela's mad cackling makes you realize the slip up you'd made, but it was too late. You couldn't take it back, and plus, in a way, it was the truth.

"Oh, I bet you fucking do." Grace moans, barely interested in you. Then again, why would she be interested in you? To her, you're just a pin-dicked submissive who couldn't even last five minutes. That dildo, however, didn't have any limits. It didn't succumb to any climaxes, and it is longer and thicker than yours ever will be. As Grace begins to tremble, you come to realize that you've been cucked by a mere toy.

"Ah... I'm gonna fucking cum!"

Grace then takes one final plunge before reaching her climax, throwing her head back as her body quivers in orgasmic bliss. As you watch her in the throes of her ecstasy, Adela says "Stand up and put your dick against her ass."

Adela lets go of you, allowing you to obey her order. As soon as you're in position, Adela grabs your shaft and strokes with renewed vigor. Grace looks over her shoulder to you and says "You gonna cum all over my ass?"

"I think so."

"You better be ready to clean it up then, Pet."

"Yes Mistress Gra-AH!"

Suddenly, Adela's spit-soaked finger presses up into your ass, causing you to jolt as your let out a moan.

"Ohh fuck." You groan whilst Adela's finger presses on your prostate.

"Is she fingering you again?"

You nod in reply. "Yes Mistress."

"You love it, don't you?"

"Ahh... Yes Mistress."

"You wish this big fucking cock was up that asshole of yours, don't you?"

"YES!"

Suddenly, you erupt onto Grace's round ass, plastering it with a few ropes of cum. Adela continues to stroke until she's certain you're completely drained. Once satisfied, she retracts her finger from your ass and says "Get down Pet."

You immediately obey your Queen's order and begin licking your cum off of Grace, once again getting a taste of the submission and humiliation you so desperately craved.