When a man dances to music in such a manner that his penis jiggles in rhythm with the beat of the music. In its most common form, the male is nude and his dancing technique is centered around pelvic thrusts. Some scholars assert that this is the male equivalent of Twerking.
While Matodgey wasn't a great rave dancer or square dancer, his Log o' Rhythm stylings were an unparalleled hit with the ladies.
I'm impressed he maintained his Log o' Rhythm despite the song being 110 beats per minute. No wonder he is sore.