"performing a sex act under cover of a juggler's hat"
That certainly could have been worded better. In my head I pictured a midget sitting on the head of a juggler, hidden from view by a top-hat, rubbing one out - which raised the question of how did the girl know what he was doing up there? I guess a 'juggler's hat' is a specific kind of hat, and not one belonging to a juggler.
