Here’s the stoner rule of the day: always save some green!
That means that, if you take the first hit off a bowl or bong, you should only hit it from one side, that way you get a bit of the green unburnt weed on top, but there’s still more green unburnt weed on top, on the other side of the hitter. This way the next person in the circle will get some greens as well. Even if you are the only person smoking, you’ll enjoy it more if you get a couple hits with greens rather than just one.
Of course this can’t continue forever. Depending on the size of the bowl, you should get at least two, maybe three or even four green hits. (If you’ve got a Cheech & Chong-sized bowl, you’ll get like a dozen).
Also don’t expect new smokers to follow this. A lot of people like to show off how much they know, but new people won’t know or understand what this means. Let them get the hang of smoking a bong first, then hassle them about this.
For the record, I don’t know of any scientific evidence that smoking “the green” gets you higher than smoking “the black”.