(After this I'm calling it a day.)
You slammed right into Rusty! As the both of you slide down, shook by the impact, your parents take this as the moment for them to flee. You hear them rapidly going down the stairs, and out of the house, not like it will be a problem.
You get your attention back on Rusty, who is trying to wriggle is way out of under your body, or at least was, until his cock, brought to an oversensitive state, brushed against yours, both of you whimpering in pure arousal, shivering from the pleasure.
This simple contact seemed to make him more docile, and as you notice that the dog has calmed down, you let go of him, but growl.
The message is clear : Either you can have a good time, or I tear you to shreds if you try anything.
Looking down, bowing before you, you know that you've settled your dominance over him, the feeling of commanding bringing forth another wave of lust, you cock throbbing, sending a small amount of pre right on Rusty's wet nose. By now, he eagerly licked the salty, clear fluid from his muzzle, him throbbing too, almost pleading you to do something, anything, just SOMETHING.
You motion to behind him, knowing now that he won't try to escape, and the dog instinctively move his ass up, lowering his upper body, as you get near his asshole, sniffing it.
Gently, you start to lick at his entrance, the taste, while awakening a slight disgust, making you even more lost in the feeling, you just have to do it. If you don't mount him now, you might as well get neutered, cause you're currently on the verge of blowing your load just there.
During that time, the feeling of your licking had aroused Rusty even further, and he nearly lodged his hole in your face, his canine member quivering, slick with all the fluids leaking from it.
Going back a few steps, you leap on him, lifting on your two hind legs. When at Rome... well.
Wasting no time, you score the bullseye and enter in one go, half your member already in, and both your mate and own panting increase, he letting out a yelp of surprise at first. You start to rapidly thrust back and forth, you hips pistonning violently against Rusty's ass. You feel your balls, somewhat bigger then his, slamming against the second pair, every shock sending jolts of pleasure down both of your spines.
As you increase even more the fast pace of your bucking hips against your mate's rear, your knot start to inflate more and more, slowly getting bigger, as your session last for several minutes.
Again and again, the ball of expanding flesh slid in and out of the second dog's hole, getting it in and out more difficult by the second, and soon, you found yourself pushing and pulling to thrust you knot in and out of Rusty's rump.
Soon, on the verge of exploding, you start to buck even more violently, and at one point, your knot, now fully engorged, enters one last time your mate, locking you together as Rusty let out an howl of both pleasure and pain. You finally decide to lean on him, and bite his neck gently, but holding him firmly at the same time.
You thrust grows erratic, without a proper rhythm, as you can feel your climax growing closer, nearer. All at the same time, you think you must've pushed against you companion's prostate, as he his currently spilling pre all over the floor under the two of you, now thrusting too, instinctively matching your speed, feeling all the more better.
In the end, unable to take it anymore, you howl deeply, climaxing in a way you've never even dreamed of, flooding your mate's interior with your canine seed, to the point where some starts to leak between his hole, and your still fully expanded knot, keeping you two firmly locked up.
As you came, finally claiming Rusty as your own forever, he too followed suit, spraying his seed all over the floor, the mess sticking to you fur, getting you both all messy, him joining your howl.
Finally, you both come down of your sexual bliss, and looked, shocked, at the biggest mess you've ever seen, cum was sprayed everywhere, mixed with the more fluid precum, which had pooled so much that it had started to spill itself down the stairs due to the house being slightly tilted forward, being constructed on an inclined terrain.
Waiting for your knot to deflate, your panting slows enough to let you talk, just as you and Rusty snuggle together.
- What *pant* a mess. I think *pant* that mom and dad will be furious... whatever *pant* I don't care.
Rusty whimper back softly.
- I'm sleepy, maybe we should just rest for a bit?
You simply nod, and still stuck together, you eventually fall asleep, right in the mess, getting both of your furs even more messy, but at the moment, you couldn't care less. You had just mated your former pet, you were now a dog with human reasoning and a hell of a libido, but things couldn't be more perfect to you. You rapidly fell asleep.
When you woke up, you...