Miley Cyrus -- Pulls a Monica Lewinsky on Bill Clinton Impersonator

Miley Cyrus proved she knows how to party in the U.S.A. AND Canada Friday night ... by simulating fake oral sex on stage in Vancouver on a Bill Clinton impersonator.

It was all for the debut concert on Miley's "Bangerz" tour -- which was filled with little people dressed as joints, giant stuffed animals, and a lot of ass -- but the big finish was her rendition of "Party in the U.S.A.."

During the song ... Miley's dancers dressed up as famous American icons to pay tribute to our country -- and when Bill hit the stage Cyrus quickly dropped to her knees in his honor.

Might wanna dry clean that blue outfit.

Just sayin' ...