used when a personal innacurately calls another person a smut (slut). They are too naive to realize that "tums" is simply "smut" backwards. clearly
those who use the word "smut" arent the brightest crayons in the box.
person: "You're such a smut."
awesome person: "oh yeah, well you're a tums."
person: "what does that mean?!"
awesome person: "if i weren't a 'smut' maybe i would tell you."