Chain of Laughter

When your smoking marijuana with all of your friends, and one person starts laughing, causing the other person to laugh, and so on. This usually ends up with all the friends laughing at once like retards until someone realizes that they are all laughing at nothing - then they laugh even harder.

Last night I started the chain of laughter while holding in my hit because I started laughing my ass off because it felt like the THC was tickling my throat.