I’ve both layered cover on top and away from app points without any noticeable differences yet.
I’ve also applied on chest, wrists, elbows, forearms, and anything exposed like the top of my hands (not a big fan cause when you wash your hands the mones are gone).
Rule of thumb, in the wintertime, all neck area, back of head (exception of products containing Androstenone). In summer I try to put as much on my arms as possible.