Professional wrestling terminology.
Face pop is the reaction an
over babyface wrestler gets from the crowds at live events. Being the 'good guy', the crowd will typically cheer for him during his match, chant his catchphrases along with him and hold up signs about him. The biggest face pop in the world is that reserved for
The Rock, although every over face will be the recipient of face pops when the first few notes of their
entrance music hit, viz.
"IF YOU SMELLLLLLL....WHAT THE ROCK....IS COOKIN'!"
*rampant face pop*
The corollary to face pop is
heel heat.