You usually say it to someone who is either freaking out or said something stupid or out of line.
The act of being vibe: Viben.
"Dam those shrooms are hitting me bro! Im seeing my dead mom sitting on that bench over there! fuck shes coming over..dam bitch get out of my passanger seat! Shut your mouth! stop talking crazy bitch!"
"Fucking vibe bro.."
"Nah its straight now; shes just viben."
2No. U just think he's ugly. Stupid.