Rihanna's All Over Drake's Face in Miami PDA

Rihanna and Drake moved their lovin' south to Miami and made it blatantly obvious nothing's under wraps anymore.

They spent Tuesday night getting very cozy at E11EVEN nightclub ... where RiRi rubbed his face in a way "friends" just don't touch each other.

Fact is they've been inseparable since Sunday night at the VMAs -- but friends close to them tell us they've really been a thing (again) since January when they shot her "Work" music video.

We're told all the guest appearances at each other's concerts this year haven't been just for show -- it was to spend as much time together as possible while touring.

The friends say they've seen this movie before, and even though it's not always a happy ending ... this is a longer stretch for them than usual.