I'm guessing, based on the other stuff in the book, that certain people... I don't want to call them vulgar... took an existing term and gave it a more subversive... I don't want to say vulgar... meaning. I mean, that's usually the case in the book. Occasionally there are original words or phrases but a lot of times they're just adaptations of existing words.
OED does not list tussy-mussy, but it does list tussy: "A cluster, posy, or knot of flowers or leaves; an ornament of silver or gold of this form, forming a buckle or the like."
OED, interestingly, lists tuzzy-muzzy as the main spelling and tussie-mussie as a modern variant: "A bunch or posy of flowers, a nosegay; a garland of flowers. Also fig. Revived in 20th cent., usu. in form tussie-mussie."
"As popular name of particular plants or flowers (see quots.); also, a bur."
"Dishevelled, ragged; fuzzy. dial."
And the third meaning (I post them here out of order): "See quots. slang. Obs.