I assume you’re talking about the traditional version that consists of a kirschwasser-soaked cherry surrounded by a liquid syrup, coated with chocolate.
You start with a cherry that’s been macerated in kirschwasser (cherry brandy), then dip it a couple of times in melted confectioner’s fondant (a sugar paste that turns liquid when warmed). The fondant dries to form a thick sugar crust around the cherry. This is then dipped in chocolate (traditionally, the stem is still on the cherry).
Once the macerated cherry is enclosed in the chocolate coating, the booze-laden juice of the cherry begins dissolving the sugar crust around the cherry, turning it into a syrup after a few days. This is the liquid that anoints your chin when you bite into one of these.
Personally, I’m not a big fan of these, but it is a cool trick. Everyone wonders how that syrup gets dipped, but it isn’t yet a syrup when the dipping is done.