Lloyd may want to add a little pine tar to his dancing shoes ... because he straight-up slipped mid-show and nearly smacked his chin on the unforgiving stage! The R&B singer was performing down in Alabama Friday night ... and, while his backup singers hyped him up to begin his song "Girls Around the World," Lloyd -- dressed in a bright yellow suit -- showed off his fancy feet. Check out the clip ... Lloyd's spinning in circles, kicking up his feet and he slides his left heel behind his right