Pre-Singing

When you're singing along with the radio to a song you like, you start singing before the first verse starts. Adverse effects include but are not limited to: trying to sing loud so people don't notice, then quickly changing the station, or the disapproval of your friends. (Usually in the form of laughter.)

Sal: Ticking away the moments that make up...
Brendan: Shut the fuck up you tool, you're pre-singing
Lee: HaHaHaHaHa, faggot!