It's a surface integral of a vector F over a surface S. I guess they are extending the joke from 1D to a 2D surface which is smoothly integrated (peeled).
A woodchuck would chuck as much wood as a woodchuck could chuck if a woodchuck could chuck wood.
It's a classic tongue twister!
Would you like to try another one?
Austria is probably the English-version of the German name which translates to "Ost"- Eastern + "Reich"-empire.