This is a term associated with rock music, notably punk rock as this is what a given band member would yell out right before starting a song at a concert. It was made famous by the New York punk rock band The Ramones
, whose bassist Dee Dee Ramone
would always yell out before every song
and sometimes even during them.
"Dude, you think Dee Dee's voice gets tired from yelling 1-2-3-4! all the time?"