Student or Learner
Can you help me with this sentence's meaning? It is said in the context like this:
A: I'm asking you very simply. Are you in or out?
B: I'm hear, right? What's this? A test?
A: No, I'm just crosing my 'Ts'. We go up there, there's no turning back.
What does crosing 'Ts' mean hear?