A C-store I sometimes visit for coffee stopped offering Stōk Coffee Shots. When I asked why, I was told that high schoolers were adding large numbers of coffee shots to Coca Cola for a serious caffeine jolt. A few days ago I added unsweetened Stōk at about one shot to six ounces Coke. Nice! The flavor is very good and the reduced sweetness even better.
N.B.: I am so habituated to caffeine that I did not notice any drug effect, but YMMV, so give that caffeine level a thought.
OOOPS! Almost forgot! Add the Stōk after pouring or dispensing the Coke or you will have to deal with major foaming.