The dragon only glares at you. You don't normally stoop to such a level, but it seems you'll have to make an exception, especially seeing as how he enjoys causing pain to others.
"You think I will submit to you?! You-"
Seeing that he has no intention of obeying, you put your foot into his mouth as he's speaking, causing him to gag. He looks up at you in hatred, but clearly knows he's at your mercy.
You only grin darkly at this. You take your foot out, and gesture for him to turn around. He does so, albeit begrudgingly.
You lift his large tail and brandish your rubber lizard cock, and thrust it up his rubber tailhole, causing him to roar out in pain. He struggles to get away, but you stab your claws into his shoulder, causing him to cease. You notice much like how you bled green goo, he is bleeding goo as black as him. Within moments you establish a steady rhythm. Loud squeaking results from the grinding. Eventually, your cock spurts rope after rope of green lizard goop into the rubber dragon. The dragon roars in pain and bliss as he himself spurts out a loud of black goop. But you suddenly notice that the black dragon suddenly feels... Wet. Or wetter than usual, as even your new body is still slightly slimy. But he feels as if the latex is melting off of him.
You take your cock out of his tailhole still filled with your seed, and rise and watch as the black rubber dragon appears to melt.
You gasp as within moments an inky black puddle of goo lies your feet, with a naked man lying where the black dragon once was. You scowl in disgust.
But then realize you just reversed his transformation!
"I-Impossible... I made it so that the symbiosis was utterly permanent. It's almost as if the sentience gained allows for it to reverse the transformation..." The man that was the dragon moments ago sputtered.
You can't help but realize what this means. You yourself do the opposite of what the other latex animals do. And all because you aren't under this terrible man's control? You notice he tries to rise up, but you place a foot on his chest to keep him down. You glare into his eyes, which are still red.
"You're probably thinking they're no longer under my control now, aren't you?" The man says smirking.
You hiss, resulting in him laughing madly until you stab your claws into his chest again.
"Y-You must fail to realize that I was merely the 'host' of the symbiote. The symbiote is the one controlling them. And unfortunately for you, it's gone!" He says laughing.
You quickly notice the black puddle is gone, and mentally cursed. It must have slipped away while he distracted you! No doubt it will find another host and take control of it in order to continue it's creator's plans...