When a girl or guy stares at another guy or girl who they think is cute for long period of time (stalker like). This is to be used as a warning to warn the person that someone is staring into the very depths of there very soul for 5 hours without taking any breaks. Its is best to avoid a Code Yellow if at all possible to prevent any discomfort! To warn someone of a Code Yellow, just say "Code Yellow" or, for singal purposes, say "Yellow" in sign language.
"He/She won't take their eyes off you! CODE YELLOW! RUUUUN!"