«طَوَّافُونَ عَلَيْكُمْ بَعْضُكُمْ عَلَىٰ بَعْضٍ»
You frequently move about among one another.
The textbook uses frequent coming and going as an operative explanation for easing certain permission-to-enter requirements. Applying the same burden at every moment to people moving regularly within a home could create hardship.
The example shows how a Qur’anic expression may point toward a legally relevant characteristic. Here tawwafun does not mean circumambulating the Ka‘bah; the context concerns repeated movement among people in the household.