Doesn’t matter if Watsky thinks he’s going to win or lose, he stays confident, betting on himself every time. .

The main reason labels keep artists is that they make the label money.
If he makes the label money, they’ll keep him signed. .

Gambino’s skills on the mic are excellent.
If she’s impressed about his rapping, he cautions her that she’ll be very pleased with a sexual performance.

He ‘murders’ the beat, which means to put a great song down on it.
He does this like nobody is watching him, much like a real murderer would do, so that there are no witnesses to the crime.
This could also refer to the fact that he acts like he doesn’t care what others think of him, so he literally raps like nobody is watching him.

Gambino likens his track to eating a turd.
When you eat a turd, you’d most likely spit.
Since spitting is another word for rapping, Gambino is spitting ‘real shit’, which means the cold, hard truth, much like he’d be spitting real shit if he ate a turd.

he knows how it feels to fail, because he’s done it plenty of times before. .

This is another continued reference.
Childish introduces himself as ‘the kid with the voice’, as in many of his songs he talks about how his voice is often perceived as annoying.
This line is from the perspective of a listener, complaining about having to listen to another CG song.
However, CG ends up proving this same listener wrong.

This is a fairly clever wordplay.
The first thing that this line projects is that he is calling himself dope, and talks about wearing a white hood, much like a Klu Klux Klan member would.
However, he goes on to state that he’s not Ku Klux Klan, and this helps the listener realize that Gambino is talking about white ‘hoods’, as in ghettos.
Gambino is saying that he’s cool with the average urban white listener.