If you want to froth your milk, you can follow the below instructions. Note that not all non-dairy milks will froth, if you're using a vegan milk. If you don't want to froth your milk, you can skip the next two steps and simply heat your milk in a small pan on the stovetop over low heat until hot but not boiling, stirring every 30 seconds or so.
To do it manually with a metal milk-frothing pitcher (basically a very tiny pot) and a normal whisk or handheld electric milk frother, pour the milk and honey into the metal milk pitcher and place the pitcher on the stovetop over medium heat until the milk teaches 140 to 160 degrees Fahrenheit, stirring it every 30 seconds or so. Remove the pitcher from the heat. If you're using a normal whisk, it has to be small enough to fit inside the metal pitcher.
Place the whisk in the pitcher and clap your hands flat together on either side of the handle. Rub them back and forth (like you would if you're warming your hands) to spin the whisk around. Slowly, foam will form on the top. If you're using a hand-held electric frother, submerge the whisk end of the frother into the milk, and turn it on. Froth until a layer of foam forms on top that's about 1/2-inch thick. (Also, make sure to turn your frother off before removing it from the milk, otherwise it will flick drops of milk everywhere).
Evenly distribute your milk and foam between 2 heat-safe serving glasses. Evenly distribute the hot brewed rooibos between the 2 glasses. Serve immediately and enjoy!