I gave up on teaching popsicle "no"... he's being selectively stupid about being disciplined/trained.
At one point I decided to be less subtle, and when he chewed on wires I reached over and smacked him a little. He barely acknowledged it and went back to nibbling. I smacked him again on his side, and he turned, gave me a look that made me think I was imagining him saying "hey, roughhorsing is fine but you're overdoing it mate!". ... I THOUGHT I had just imagined it... he went back to chewing, 3rd smack, and he stopped, gave me a look which clearly said "IT WAS ON PURPOSE???" and then he gave me a glare, then he ran back across the room, went into his cage, and sulked in his metal cooler house. Utterly completely sulked.
...
I gave up.