Definitions by Rachael and Nicole.

HISSS 

The act of making a wheezing noise while laughing.

"OMG! what you just said, made me laugh so hard i started HISSSing! HISSSSSSSS!"

HISSS by Rachael and Nicole. August 23, 2008

modi 

The act of laughing so hard in a public quiet place, that you have to put your head down in your arms so no one hears you. Sometimes you laugh so hard you hisss

my friend texted me a joke and i modi in public.

modi by Rachael and Nicole. August 22, 2008