It's like watching someone come down from a high. Technically they are doing just that. They get pretty intense, very demanding, can't handle the calmness and relatively (to the stupid show they just watched) quiet environment. And they know it too. Both my kids express that finishing watching shows on the iPad doesn't make them feel good. They're very aware of it. Now that it's nice out they would rather skip it altogether and go on a hike early in the morning, so I don't mind so much when they do opt for an iPad kind of morning once in a while.
My son is going through the exact same thing! My theory is that there’s a dopamine adaption going on, or sthg like that. For him, it’s the same with audio books or digital games btw. The longer he consumes content, the longer the cool-down phase lasts after that, though the max duration is about 15 minutes — after that he is fine. What he does differs everytime, but it ranges from swearing to crying to just poking at food with an absent look, saying nothing.