A bit of backstory:

“Something” happened. When White dropped Black off “somewhere” for the night, he asked; “Will you be okay on your own?”

Black: yeah.

-you sure?

– yeah, I’ll sleep.

– Don’t cut

– I’m too beat to do it.

And that explains White’s anger in this scene when Black says he’s cut.

A habit which started as a way to not disturb his father’s sleep, coz blind old man has sharp hearing, empowered by the fact that White is always crashing on a couch somewhere and stays up at night watching TV, then ended up becoming a thing to his liking; watching a series or sports with the no audio.