LIQ=laugh inside quietly. Used in an instance where something is amusing but not quite funny enough to make one actually laugh out loud. Allows for a better distinction between various levels of amusement and prevents the constant lying of people claiming they're laughing out loud when they're really not. Especially useful for puns.
I can't believe I completely blanked on that girls name. I've been in her class like all year. LIQ.
I hate when a good joke about airplanes goes under the radar. LIQ.