Have you ever tried to explain an inside joke and started laughing in the middle, only serving to make the whole thing more awkward than it already was? The other party is looking at you like you are in the throes of a seizure, the look makes you laugh harder, before you know it you are choking on your own snorting piggy laughter at a joke you can't get out -to someone who will never think its as funny as you do? No? Just me? Ok, whatever gets you by.
I've done this, and let me tell you, when you finally start getting enough oxygen to your brain again you realize that you had better NEVER stop laughing because your laughter is making them laugh and when that stops and you have to explain out loud the actual thing that started it all, it is going to be a huge letdown and they will do that sad little not-a-whole-laugh and then sigh for you. With you. But they are wondering what you have smoked and you are wondering how to change the subject.
The secret to this (yes there is one) is to be smoking something. No one ever gives the sad face to a pot smoker who is indulging in a good belly laugh about something they don't understand. You laugh along with, then when its all over, you believe you were laughing at something funny and not just to go along with the crowd. Pot is so inclusive like that. Not like that "You aren't cool enough, get out of the bathroom" attitude Cocaine has. Maybe its the contact high. See? Cocaine is a stingy dick.