JDGAB, an acronym ('J'Name doesn't get any bitches) used derogatorily against people specifically boys/guys starting with the name lettered 'J' who cannot seem to get into a relationship with girls...
A Jugasaurus-Rex is the name given to a female with extremelylarge breasts.
The phrase was made famous by Neil from t.v show 'The Inbetweeners' where he spots a girl in the park and says, 'Hey guys, look at that Jugasaurus-Rex!'.
'Hey Lewis, Jugasaurus-Rex at 5'o'clock!'
'Woah, Your a right Jugasaurus-Rex!'
'Don't you think that PamellaAnderson is just one huge Jugasaurus-Rex?'