Rage and anger! He growled, and I said, "Okay, now's a good time to use words," and he was so good about stating how angry he was, and bringing his voice down when I asked. But, so angry! It was startling. At one point he even punched the back of my seat, which was a pretty solid punch even from the passenger side of the back seat, which gave me some new information on why it's such a problem when he drastically mis-reads another kid's social cues and goes all Angry Hands on them: J is a big kid and apparently he can put more force into a punch than several adults at the dojo.
"I am so angry at you! I'm never going to snuggle you and Mama again! Except for the morning snuggle."
(The morning snuggle is pretty important around here.) We talked a bit about how threats weren't really okay, but mostly I was happy he was talking it out instead of having a tantrum seizure in his carseat. I was also trying to explain that there was no conspiracy to deprive him of computer time, it's just what happened, and maybe before taking his revenge on us he should talk to Mama about what happened. Finally I took a step back.
"So, J? I feel like you're not listening to me. I keep telling you that no one meant to keep you from having your computer time, and you keep threatening to withhold snuggles, and I don't feel very good that you're threatening me when I don't feel like I've actually done anything wrong."
There was a few minutes of silence, and then I heard him laugh: he'd picked up one of his books and started giggling at whatever he was reading. And everything was fine for the rest of the dropoff.
No more snuggles, ever! Except for the morning snuggle. SO CUTE.