When I was in therapy a few years ago, my therapist introduced me to a technique she called Wild Mind. The idea is simple: just let yourself do what you want from moment to moment. Follow your impulses. If you feel like cleaning, start cleaning. If, halfway through, you get peckish, eat whatever food occurs to you to eat. Take a walk while you're eating that apple, and if you want, stop and look at the scenery when you notice something striking.
Wild Reading introduces one constraint. Follow your impulses, but while staring at the text you need to read. If you have a dense textbook, perhaps you'll idly flip through the pages. Maybe you'll glance at the headers, or skim a sentence or two here and there. Stare at the figures. Count the paragraphs. Maybe you'll find yourself drawn in to read the sentences themselves occasionally. Whatever you do, follow your impulses, no matter how shallow or lazy they seem, as long as you're staring at the text while you're doing it.
I'm just starting to experiment with it, and I like it. But I see this as a hypothesis, one that might be worth experimenting with for several hours on a single text to see how it works for you?