OK, all the womenfolk will please leave the room right now, this message is not intended for your eyes.
"Gazelle in the park" is a way that one British gentleman would inform another British gentlemen at a dinner party, that there was some food
in his beard. If anyone at the table overhead it during the chatter of a dinner table, it would easily be instantly recognized, or totally unintelligble, usually the latter, especially to the ladies.
Somewhat akin to the cruder Americanism "You'r losing altitude" when someon's fly isn't quite zipped.
See now, Scots in kilts never have THAT problem.