"I wiped it off!"

I do not know how this expression came about...but it is something I hear constantly from Violet and Calvin.  If one makes the other mad, the one offended thinks they have the power to reverse the effect by saying "I wiped it off!" For example, if Calvin hits Violet, she will say "Calvin, I wiped it off!" as if to tell him he doesn't get the satisfaction of hitting her.  And depending on the degree of offense, the word "wiped" will get louder and more intense.  What gets me laughing though, is when I hear "Wipe! Wipe! Wipe!" over and over...