Place chocolate in a heatproof bowl (preferably with a spout), and set aside.
Combine milk and cherry juice in a small saucepan and heat over medium-low heat, whisking frequently. (The faster you whisk, the foamier the milk will be.)
When the milk mixture looks like it's about to boil, remove from heat and pour into bowl over the chocolate. It's very important not to let the mixture boil, or it will curdle.
Let sit about 1 minute, then whisk until completely smooth.
Pour into a mug, add desired amount of bourbon, and enjoy.