Erholung
What the teacher did was appalling, but why did it matter that her top was falling down? When will we moved beyond being a society controlled by the moronic idea that female breasts differ in any way to a male’s?
It matters because (A) the girl found it embarrassing (B) regardless of male or female if clothes are coming off it is not good to continue pulling them off of someone screaming NO and (C) women's breasts DO differ from man's in size, shape, ability to breast feed and various other obvious ways. If a guy said "my pants are falling down" and only his butt was exposed (despite majority of male and female butts looking same" it is still wrong for a private area of his body to be exposed against his will.