"Master Jack," Bruno said as he kissed Jack's nipples and massaged his shoulders, "Thank you for giving me John-john, but you didn't have to fix him. I could've turned him into my bitch boy even if he had his nuts. Or you could have turned him into a real bitch, and had grandnephew puppies?"
"No, Bruno, I promised you a permanent human dog sex slave, and whoever put on the dog suit could have changed back into a human as long as they had their procreative organs. That's how magic works. A fixed dog cannot be anything but a dog, he cannot become a human eunuch. So as long as John-john is ball-less, he is truly a dog. And hopefully, like a real dog, he will forget that he was ever anything but your bitch boy, Bruno,' said Jack with a tinge of regret in his voice.
"Oh, does that mean he'll die after 10 years or so, like a real dog?" Bruno asked.
"Huh? No, of course not. He retains the human lifespan that he was allotted, even if he is not human anymore."
"Oh, good. So I should get at least 50 or 60 good years out of him," Bruno remarked licking his the length of Jack's growing penis, and running his tongue up Jack's torso to end in a deep kiss on his mouth - er, or in it.
"Mmbgt nuhmmurgal," said Bruno while kissing.
"What did you say?" asked Jack pushing Bruno away. Bruno was his magical familiar, but he had to watch out for the beastie playing tricks. He was sure Bruno had something to do with John putting on that dog suit. A test probably? Would the wizard honor his vow to Bruno? Or would he break his vow to save a relative? He might be able to do both, but it would be tricky.
"Oh, master. I just commented that it's too bad that your nephew is not immortal like us?"
"He'd need his nuts back to make him so," Jack commented, "As I said, and as you know, magic - at least our type of magic requires procreative force. The magic of life, if you would. But less business talk, and more loving, Bruno!" Master Jack ordered.
"Roof!" growled Bruno happily wrapping himself around Jack.
Then Bruno glanced over his shoulder at the dog john-john.
"Here boy, here, john-john!" called Bruno.
As much as John wanted to resist, he felt compelled to be a good dog,and obey. He leapt on the bed at the feet of the embracing men.