I think it's because first timers can't hold it for shit. I remember the first time I did it with my friend. The smoke felt like it burnt SOO bad I couldn't even hold it. The next time, I held it in a lot longer at got really wasted. Now, when I hit anything strong, I can hold one huge hit for like a minute and get high off of one hit. Then I have like 2-4 more hits to get wasted as fuck on.

I've also stopped caughing completely, and it seems like I get way more high that way. my lungs burn for like 10 minutes after I'm done smoking as my high gets stronger and stronger.

So, tell them to hold it in for a while, and don't let them cough.