U.T.G is simply short for Untamed Gurillaz, or Untamed G's the clicque popular in Dallas, Texas
U.T.G 4 lyfe, hoe ass nigga
This had the same meaning as "crab" or "E-Ricket". Either way, it means dissin crips otha known az crabz
"Man, im'a pop me some scrabz today my nigga, you down?", "Hellz yeah bro, I'm always down"