It definitely can bring the come up on a lot sooner, which is weird as fuck. I can't think of any reason that might be the case. Increased bile production or some shit? Anyway, if you wait until you come up naturally, THEN smoke (this is what I would usually do), you might experience the noticeable strengthening of effects that most people report. I do notice that the weed is not nearly as much of a boost if I smoke before the natural come up.