Real answer:
It's bomb as fuck, do it. But don't over use.
Take the paper you're going to roll the blunt with, dab (I SAID DAB!) your finger into the bottle of prometh and smear it all over the inside of the paper (where the weed goes). You'll only need to dab your finger in once to cover the paper. Place grinded weed in paper (on the side with the prometh) and roll it up. Let it dry and set a little bit first. Sometimes even after rolling i'll take another dab and let i drip into the beginning of the blunt.
Never use too much, just enough to cover the paper. Or else it'll be too wet and you're pretty much smoking only chemicals. That's if it even lights up.
Tastes delicious.
PS - When I say prometh... I mean promethazine with codeine. The real syzzurp/ lean. Not that bunk ass yellow shit.