Let your sisters use the incubus, but under your supervision

The situation gets to you more than you would normally like, but normal might as well have been a millennium ago instead of just a day, so you don't try to resist the power trip as much as you could.

"Very well, take him if you're so ****, but keep in mind your vows," They're stripping off their dresses before you finish your sentence.

Standing back, you allow the both of them to drop and get at Xall's outsized member. You watch as they lap on opposite sides of the shaft, ready to step in if they or the incubus move to preform any untoward actions.

Glenda and Anya slurp all over the phallus; try to fit a testicle in their mouths, taking turns bobbing the length down their throats, and dragging their tongues from root to tip, where they lift temporarily to engage in a sloppy kiss.

Xall is delighted to finally have some more attention, straining against his bonds and babbling out some delirious dirty talk.

"Oh yeah, take it, the both of you! Suck it down and I swear you never have anything better! Sabine, Sabine you should join in, it'll be so much better as a group!"

"Watch yourself boy," you say shortly in reply, "and don't you dare try to break loose, or try to prolong this."

Oh, that's something you hadn't considered, only Xall knows when he's ready to turn back, and like this he likely won't be inclined to follow through.

That won't do. "Xall, this is your only warning," you begin, "swear that the instant you have enough energy to change back, you let us know, or I'll just have to pull these two off you at intervals to interrogate you, and leave you like this if I get bored."

"I will, I will, don't worry! No need to cut me off prematurely! Just two or three climaxes should do the trick."

Satisfied with that answer you lean against the back of the cave, keeping your fingers on the hilt of the holy blade.

Your sisters are conducting themselves like sexstarved whores, and it isn't long before Xall spews his load all over their upturned faces with a roar. He's still hard and dribbling after his orgasm runs it's course.

Anya gets up even as she and Glenda scoop the cum of their faces to slurp up, straddling Xall's hips and moving to line him up for penetration.

You lunge down and tug the phallus out of her fingers. Anya stares back at you as aghast as if you had snatched her infant.

"Just making sure this goes in the rear entrance like we agreed is proper," you state as sweetly as you can manage, and true to your word you press Xall's manhood to Anya's tight anal ring.

"Sabine really, I'm a little more trustworthy than that."

"Not with this much testosterone floating around in and off you," you don't give Xall a chance to argue further.

"Glenda, ride his face."

Anya gasps and groans as the spit-coated shaft pushes its way fully into her ass, while Glenda grinds delightedly on Xall's lips and tongue. Soon enough Anya is bouncing in earnest and you watch as both your fellow "wives" ride your shared lover to completion.

You stand again when they both clench up, and catch them both as they slump over, maneuvering them to lie down on the piled blankets.

You turn back to Xall, exasperated to see him still unchanged.

"Just one more go, I swear," he gasps out.

"I think these two have had enough," you state, glaring when they try to moan out a protest.

"If you two are still horny, play with each other. Make a show of it for Xall here, give him some visual stimulation as motivation to transform."

"I need more than that-" you cut him off with your had on his dick. It's hot and bulging in your hands, the veins swollen and pulsing with his elevated heartbeat.

"I've got you now," you tell him, "You just lie back and enjoy the show.

The incubus complies, grunting and spurting precum with every stroke of your hand on his meat as Glenda and Anya embrace and grind their quims together. You decide to indulge in some experimental dirty talk to facilitate your ministrations.

"Look at those two going at it, their lithe figures dancing together. Such gracile little nymphs just consumed with desire for each other. Don't you think find that to be just the purest expression of eroticism? My hand on you member, it's so good isn't it? Better than your own clumsy meaty claw. Fingers so delicate, yet do nimble, so deft. That could be your hand Xallia, your figure. As enjoyable as I find your penis, my first preference is the female body" you whisper with heat, hearing the incubus under you sigh and moan at an increasingly higher pitch, eyes fixed on Glenda and Anya. When the both them cry out in release together, you hiss in Xallia's ear as you give a last harsh pump, "Join your sister-wives back in the experience of the fairer sex."

With a feminine scream the morphing succubus cums, balls drawing tight as they fire the last of their excess discharge and more. All of Xallia's masculine extra mass seems to be draining out though her orgasm, her body shrinking down and becoming slender. Even her cock, while still remaining well-endowed, loses a significant amount of length and girth in your hand even as you stroke her through her climax, becoming smooth and tapered, oddly feminine for a completely male appendage, and her testicles sink into her flesh and leave a new set of female genitalia in their wake.

When all her parts and features have finished slimming and softening, her curves fill in. Breasts, buttocks and hips flare out before your eyes as the newly returned succubus mewls and squirms in your arms.

At last Xallia finishes reforming and collapses in your arms. She looks up at you with dreamy, half-lidded eyes.

"Welcome back," you say with genuine warmth. Without warning you slide a finger into the succubus' new slit, ignoring her intake of breath as you trace over her fresh hymen, "My new sister-in-waiting."