Rosario Dawson -- Plays Tonsil Hockey with Jenny Slate ... (No Reason Necessary)

Rosario Dawson is here to help you kick off your weekend the right way -- by sucking serious face with "Obvious Child" star Jenny Slate.

Not that anyone requires an explanation ... but the make out sesh was set up by New York Times Magazine as an awesome year-end celebration of great acting.

They actually shot 9 different kissing scenes -- including Kristen Stewart and Chadwick Bozeman, Laura Dern and Steve Carell, and Reese Witherspoon and Benedict Cumberbatch.

But Rosario and Jenny's scene wins hands down ... as they go at it in the back seat of a convertible.