(Whether you choose dad, mom or Rusty, they will all share common choices, so don't be surprised if there's one choice proposed more than one time, even if wrote in a different manner, it's to try with other characters.)
You start to sweat, and suddenly, you notice the scents.
The subtle scent of your cum still lingering on your parents, and the one of your dad's sperm inside your mother's cunt. Even Rusty's privates start to give off an arousing smell.
You feel your canine cock sliding out of your sheath, the pointed head already dripping precum, throbbing from the sheer arousal you are feeling at the moment. What is that thing doing to you?!
Slowly, with a new kind of hunger in your eye, you start growling as you go nearer to the trio of dogs in front of you, who suddenly step back, scrambling to not collide into each other.
You hear the two older dogs barking something at you, but you don't care. All you care about is to get relief, whatever means are necessary.
As you look into their eyes, you know that you've got the upper hand (paw?), they are all whimpering in fear, despite your own scent exciting them, the males just as erect as your are, and the female's vagina slowly dripping with her juices, still mixed with the older male's cum.
The anticipation alone could make you cum on the spot, your knot already expanding, although not much for now.
Tired of standing there, you leap toward them, and collide with one of the dogs, next thing you realize is that...