Saying used to get a party started or to start drinking alcohol. Defined by Dean Brody in the song Roll That Barrel Out. Refers to rolling out a whiskey or wine barrel.
Jake: Hey what you sayin' girl? Wanna get a buzz on?
Your friend: "Last night I lost everything. My girlfriend dumped me, I lost my job and I'm starting to lose my grip on reality. What should I do, man?"
A theatre term: An insertion of a small prop during a scene involving some kind of roll to stay out of view of the audience. Said roll does not have to be a barrel roll, but most usually is. Usually referred to by acronym; LBR
"Dang I forgot to put that knife out on stage and had to pull a lavarian barrel roll."