What does the phase its getting deep mean?

Answer 1

1: This phrase is used to describe a situation in which, one person is thought to be telling untrue stories to usually two or more people at the same time. The listeners will indicate to each other that the story teller is lying, or otherwise stating falsehoods, by one of the listeners turning to the other listener and saying, "It's getting deep in here."

2: The stories, "lies", that we're listening to, are causing the room to fill up with the rubbish that is pouring out of the story teller's mouth as he continues to speak untrue stories. The room would then be described as "getting deep in here"...deep with rubbish.