“Come here, you little fucker. You’re adorable.”
“For the love of God, can you learn to cover up your poop?”
“For the love of God, stop licking your brother’s butt.”
“The repairman’s coming over, so I need to lock you in the basement for a few hours.”
“Who is my little fatass? Is it you? Yes it is!”
“We’re leaving for a week. The neighbors will periodically check in on you. Try not to kill each other while we’re gone.”
“How are you so fat? I mean, honestly. How are you so fat?”
“Your brother is not a raging moron. Why can’t you be not a raging moron like your brother?”
“You are so cute in your incompetence.”
“Aw, who is my emotionally manipulative rat bastard who is only pretending to love me for food?”
“If you weren’t so cute I’d boot you across the room.”
“Who wants a fresh bag of drugs? I’ll sprinkle some across your toys.”
—
One phrase I can use at my cats, and potentially with my future children as well:
“Yeah, keep whining. See if that changes anything.”
That (Not This) Abby Rose 
Here`s one: That`s it, keep eating. Then I can roast you for dinner.
Too far? 😀