Or the hidden reservoir in the cane?
I mean, these Pocket Shots (use this link and you don't have to go through age verification!) are just energy gel packets filled w/ booze.
Simply not the class of stainless steel flask or hidden vessel.
But look at all the excitement and news they've created-
Google search for "pocket shots"
Besides, the cane or flask can double as a weapon, just ask John Steed.