Kate Upton -- Spank Me, Flo Rida

How do you make a boring tech convention interesting? Hire Flo Rida to spank Kate Upton on stage.

Here's how it went down ... Samsung threw a "Spring 2013 Launch Party" yesterday at the Museum of American Finance -- SNORE -- but before everyone fell asleep, Flo Rida took the stage to perform, and Kate joined him in a sexy blue dress.

Convention saved.

And you gotta see what happens when Flo raps his famous lyrics ... "She turned around and gave that big booty a smack."