острич sounds weird to me as well, I guess it's got to be some sort of an archaic variant.
What word would you use if you want a person to stop what they are doing?
перестань прекрати are good, if it's less urgent you can say заканчивай, закругляйся.
Тебе не тесно? Тебе не давит(this one only about shoes I believe )
тебе нигде не жмет? I think is the most common variant for both shoes and clothes. не давит honestly I only heard in a joke about a man who gets out of jail and goes to a job interview where they ask him what he can do and he says he can dig, they ask him what else and he says he can not dig, so they tell him they won't be hiring him. On his way out he says to the secretary
Потолок на уши не давит?
the secretary says why and he says
А я на вашу контору х положил.