...troops often composed words to marching tunes, mostly derogatory of the enemy or authority...

It was reported that when one of the US Presidents was beginning his first term, the out-going predecessor recommended that he "pass the minutes" in ceremonies by creating his own words to the Presidential Anthem (Hail to the Chief). (Singing along, if only mentally, helps keep you from looking like you're asleep?) It was implied that the words would be a "personal secret" never to be revealed to anyone; but some years after leaving the office, as a former President, the subject once recited his "personal lyrics" in an interview.

It was not particularly favorable to a couple of (his own) Cabinet Members, a diplomat or two, and several Members of Congress, but was quite "singable" - - and pretty funny if you recognized the victims.

John