My friend from a fancypants private school taught me this version of "Yankee Doodle" in the mid 1970s. At the time we just thought it was funny to sing the song — which they were CONSTANTLY making us sing at that time, I guess because of the American bicentennial celebration — with all Fs. We didn't even know that a dirty word was lurking in there.

Fankee Foodle fent to fown
Fiding on a fony
Fuck a feather fin his fap
And falled it facaroni