"OMG it's big!" or "OMG it's huge!" (OMG acronym for, Oh My God!) A quote commonly used by females to describe a big penis usually when seen for first time. Though, statistics show most females use the phrase when seeing a big arachnid (like spiders.)
*Girl looks in huy's pants* OMG it's BIG!"
*Your mom sees a spider* AAAAAAHHHHHHH!!!!!!! OMG IT'S HUGE!!!"