Further to Tattie Bogle's snippet "there's a long, long worm
a-crawlin' along the top of my tent - I can remember a bit more (from some 60-odd years ago.
It's a parody of, and sung to to tune of, the First World War song, "There's a long, long trail a-winding into the land of my dreams"
It begins, "There'a a long, long worm a-winding up to the top of my tent.   I can hear the bugle calling and it's time that I went..."
can't remember the middle bit, but it ends, "... and when I return, I'll find that worm - upon my pillow - squish squash."
Wonder if anyone can fill in THE ORIGINAL WORDS to the missing bits?