Tips like this are great. It’s something you do every day, and you’ve probably been doing it wrong your whole life. Do you ever heat something up in the microwave, like big plate of spaghetti? But the middle is still cold, so you mix it up, toss it in for 30 more seconds, and then burn the crap out of your mouth?
It happens because microwaves can’t really penetrate that far into a deep pile of food like pasta, or leftover Chinese. That’s why the edges are hot, and the middle isn’t.
So instead of piling it up in a big mound, try arranging it in the shape of a donut: a circle of pasta, with a hole in the middle.
It should heat more evenly that way, so you’ll only have to zap it once. And there won’t be any hotter-than-lava sections, so you’re less likely to burn your mouth.
Apparently it helps with other foods too. For example, if you’re re-heating a bunch of drumsticks, arrange them in a circle so the meaty part is near the edge of the plate, and the bone is facing in, toward the middle.