This term stems from Jay Park's famous 'Single ladies' dance cover that he performed with the Bboy crew Art Of Movement (AOM) while at Rutger's University.
It may be used by Shoo Shoos (Bumtists) in order to describe someone who is an extremely good dancer. It also applies to any males who occasionally do a sexy dance to songs sung by female artists.
"Did you see that guy dance? He was Jaebum Fierce!"
"My gay friend wants to be Jaebum Fierce, but no one can dance like Jay Park