When a person that you know and like and have always had a mutual respect for, suddenly behaves as though they really dislike you and everything about you. That person is said to be in "Full Dick Mode".
Guy1: Hey man what's up? How's it hangin'?
Guy2: What do you care and why do you have to use crass phrases like that?
Guy1: Oh OK... I get it. You are in "Full Dick Mode" today.