Stimulants especially methamphetamine but to some degree cocaine cause a set of compulsive behaviors, tic like behaviors. Some people itch due to the tactile sensations. Some people pick at their skin. Some people clean even if the house is already clean. Some people thumb through the floor for more (GROSS). Some people peek out the windows because they're fucking paranoid freaks who shouldn't be using speed (IF YOU DON'T ENJOY IT DON'T USE IT). Some people will have stereotypical repetitive body part motions like rolling fingers together, etc.
It's really hard to explain until you've witnessed it in a variety of people and situations.
As you have a book that probably has more information than I do, want to share what it says? It might enlighten my understanding of these kinds of behavior people exhibit.
Oh and the whole "if you don't enjoy it don't use it" and "gross" isn't directed at you Burnt Offerings, it's just a general hint for anyone who might be doing these things. They are off-putting to others, even other meth users who don't exhibit these symptoms. I've seen these types of behaviors in so many people that I now believe methamphetamine is basically poisonous for like 50-90% of the population, and only a few people can handle themselves and perform well on it.