"William "Stuttering Bill" Denbrough recites this in IT (1985), but the line is not originally King's, as is often believed. It is part of a tongue-twister that dates at least to its publication in "Exercises in Articulation" in The Dayspring (March 1874), p. 39:"
January 1, 1970
https://en.wikiquote.org/wiki/Stephen_King