As for the actual drinking of tequila, I highly recommend it on the rocks. Due to its sweetness there's absolutely no need to do shots of Rosangel, even if they're off of someone's stomach. I've also made pretty swell margaritas with it using margarita mix, but the tag on the bottle gives a far more involved recipe which involves orange liqueur, Agave nectar, and not-so-random other things. While it sounds truly fantastic, my above average margarita mix did the trick and required a minimal amount of mixing and measuring and stirring and shaking. My drink ethos has always been that less involved if I'm making it is more, and Rosangel allows me to put together a good margarita under those rules.
It can be drunk straight. It can be mixed. If you drink enough of Rosangel it just may make you do the hibiscus hula, and if you drink too much perhaps, just perhaps, you'll think that you're doing the hibiscus hula with Mickey Mouse. What more could you possibly want?