An enthusiast or practitioner of groundfighting, as seen in martial arts like Brazilian Jujitsu or Koshen Judo; anyone caught up in the current MMA fad, which has a heavy jujutsu component. As groundfighting can involve hours of intimate grappling in close proximity with members of one's same sex, the term is intended as derogatory for those fighters who only know the game of grappling, and favor it above more practical fighting methods.
I had heard that Mark had started learningpracticalself defense, but when I found out he was enrolled in BJJ, I realized that he was just another juji-fruit.
Booty fruit is fruit of the booty. Just as when a seed is germinated within a plant to produce fruit, sex produces offspring in humans. Therefore, children are fruit of getting booty, i.e. booty fruit.