I have a belt with the letter 'M' on the buckle. For some reason, the belt has recently been shrinking people to an abnormally small size. I asked the unfortunate victims how to reverse the effect, and they told me that I could set the belt to 'Wumbo' by turning the 'M' over so it says...

I have a belt with the letter 'M' on the buckle. For some reason, the belt has recently been shrinking people to an abnormally small size. I asked the unfortunate victims how to reverse the effect, and they told me that I could set the belt to 'Wumbo' by turning the 'M' over so it says 'W' instead. I tried this many times, but it doesn't seem to be working. Is there such a thing as 'Wumbo' mode, and, if so, am I following the proper procedure to activate it?