girl: alright i'm ready for sex!
guy: ok.. time for mr. petey to get hard (he pulls down his pants)
girl: oh my god! oh my god! you penis looks a lil pale and lifeless
guy: i think i'm having a sheebee-out
girl: damn right! i be out!
when something is so "lit" or "fire" that you make out a loud noise in the form of a SHEEEEEEEEESH. Usually used in combination with the :smiling_imp: (😈) and the :hot_face: (🥵) emojis.
Often said in a high pitched voice and lengthened for effect. You could say this in reaction to truly almost anything, but it is commonly used in reaction to something hype.