As soon as Yui starts to cum, Christa does too. As she clenches around Yui, she compulsively lets her cock out of its sheathe so she can spurt cum all over the ground beneath her.

While her cock twitches and spurts, she lines up her mouth with Alard's cock.

Oh wow, swallowing it down to the root is super easy! And feels really good. She hopes he fucks her throat.

While Yui fucks her, Aire's pheromones go to work persuading it that actually, she's not just a nice squishy thing to fuck, she's hot. And her aphrodisiac fluids ensure that both cocks inside her very thoroughly enjoy themselves. 

And any cocks inside her stay nice and hard no matter how many times they cum.

Yui and Alard are not expecting any of this.

Alard notices the sudden presence of spurting girldick, has no idea how to react, and so doesn't react at all. It's startling, but, the pheremones are working on him too, so that startlement fails to knock him out of horny-mode, and his brain is too busy to generate opinions.

Yui is too horny to be confused and is busy pumping as much cum as it can into the soft, warm, slick, tight cock-receptacle underneath it.

She gets to work on deepthroating Alard's dick. It feels good enough to her, and even better, the better he feels the better she feels.

And she already feels so good. As long as Yui is cumming, Christa is cumming. Each spurt of dragon cum into her pussy triggers another spasm of her cock, another thick rope of cum.

But she could be cumming harder. She will be if only she can get Alard to cum. She wants it, and so she telepathically encourages it. Won't he pretty please cum down her throat for her?

Alard has basically no resistance to this and instantly erupts, feeling like his soul is leaving his body through his cock as his orgasm rips away all control and his hips spasm upward.

Golly.

And the pleasure of his orgasm gets added to hers and it's so good. 

She's getting as much pleasure out of her pussy and throat as she can, and she doesn't want to risk her stability by reaching down to stroke her cock. And Yui's constantly cumming.

The only way for her to get more pleasure is to suck it out of Alard.

She's very committed to getting him off as many times as she can, as quickly as she can. 

?!?!?!?!?!?!?!??!?!??!?!?!?!?!?!?!?!?!?! (But in a good way.)

Oh good! She's happy he's enjoying himself. She basks in Yui and Alard's pleasure telepathically as they fuck her, and she fucks them. It feels nice to be helping people feel so good.

Slowly, she falls further and further into warm fuzzy unthinking bliss while she cums continuously around Yui's cock and all over the floor.

Alard's stamina is the first to give out. He gets less and less responsive until she's nursing on a dick that wants to go soft and only isn't due to all the pheromones and aphrodisiac.

On the other hand, while Yui can't go forever, it is a physically fit dragon that isn't going to get tired for a while.

Well, even if he isn't cumming or doing much thinking, her throat should still feel nice and warm around his cock, so she can keep it there.

Christa keeps happily fucking Yui for as long as it wants; she won't run out of orgasms to have no matter how many times she cums.

Eventually, even Yui's stamina gives out. It manages to roll onto its back instead of simply collapsing in place and crushing Christa. It takes Christa with it, though, cock still hard inside the human girl, kept erect by her supernatural advantages. The dragon's belly makes for a surprisingly decent mattress.

Alard is left sprawled out on the ground, his towering erection rapidly withering once Christa is pulled off of him.

Oh, and that psychic presence? Is still watching Aire. It's definitely been there the whole time. It had to have seen everything.

Christa, although she may be able to have infinite orgasms if she so desires it, does still eventually get tired. She only had the physical stamina to last as long as she did because all she had to do was hold still for the dragon to fuck her. She falls unconscious pretty quickly after the fucking stops.

And Aire waits. Now that everyone besides her is asleep, this is just about the perfect time for the presence to intervene. 

And she's in a very good position to seduce them if they do. The air in here is absolutely filled with her pheromones.

The air sure is full of pheromones.

Like, really full.

Is Aire sure all of those pheromones are her own, actually?

From the ways that she's starting to feel a little tempted to wake Christa and prompt her into masturbating, she really isn't.

She's not very tempted, but the idea is occurring to her at all, which is odd enough she notices it. She should be satisfied enough at this point for obvious bad ideas like that not to rise to conscious attention.

A flicker of shadow, on the roof of Alard's cabin.

A hint of movement, from the roof of Yui's nest.

The eye playing tricks. Or is it?

And then an immensely powerful telepathic voice slithers up against Aire's shields, revealing nothing of its source.

Why do you hide?

Aire keeps her body relaxed and deliberately arranges herself to present herself in the most arousing possible light to anyone looking at her from the roof.

That is not to say she isn't startled, just that this happens to be her immediate startle response.

This thing obviously knows she's here. Might as well answer the question. But how honest should she be? For all she knows this presence is working for the local authorities.

Because I don't know the risks of revealing myself, and because I can.

For far too long we have searched for the Unity. Far too long. You lay with the enemy. You must be protected.

Drop your shields. I need to know if your intentions are as you present them to be. I will not surrender myself into the protection of something that could very well be more dangerous than the enemy by my side.

An obvious thing to request and say even if she isn't an enemy of the state or the boy. Who wouldn't lie like that in this situation, if they were quick-thinking enough to do so?

Must not. Must not, in the den of the enemy.

A feeling leaks through, a fervent conviction.

We cannot. We must only obey what does not endanger you.

Well, that rather prevents her from informing them of how her "laying with the enemy" ensures that, if she is attacked in the near future, that selfsame enemy would come to her defense. Her pheromones are so useful that way. But she will not risk telling them this while the possibility remains that they are misrepresenting themselves.

I am safer than I appear, here. Removing myself prematurely would only risk additional suspicion. We may speak more in my host's abode after we return to it, if you wish, or elsewhere that does not unduly risk my health in the event that you are misrepresenting yourself.

That is not consistent with Aire's earlier claim about why Aire is hiding from her host.

This is worse than we feared.

The Unity must be protected.

In an instant, a drill-spike of telepathic effort rams into Aire's shields, carrying a payload of screaming, insensate orgasm.

Aire's shields are nearly impermeable, and her will is extraordinarily strong. She could shrug that almost entirely off, the arousal that passes through her barriers negated by her iron control over herself. But that would be the wrong way to handle this situation. No, she needs this presence to decide to fuck her and marinate in her pheromones for a bit. Then, even if it was hostile, it won't be any more.

No, instead she lets her shields down just enough to get what she needs. And then the pleasure hits.

She lets her cock out of its sheathe to very visibly spurt ropes of cum all over herself. Her eyes roll back into her head and her tongue lolls out of her mouth.

She's not actually incapacitated by pleasure, but she certainly looks it. And as she cums, her lust aura unfurls around her.

A shadowed, misshapen figure blurs out of the darkness and snatches Aire up in a pair of arms helped by a pair of sinuous tentacles. A brief moment, a brief glimpse of a single massive eye the size of a melon, before the shadows embrace them both. Aire can feel a pair of naked breasts pressing against her, though.

A breeze, a feeling of weightlessness, then rushing movement, with both the figure carrying her and the city they're passing through shrouded in darkness.

Drat, it's fast. She doesn't have the time to seduce it (her?) properly as it approaches her. Well, probably the aphrodisiac cum she's spurting onto it will ensure that by the time they reach their destination it'll be desperate to fuck her.