A term used whenever you are determined to achieve something in a game or accomplish a goal, it can be used in real life also.
"We are gonna win this thing!"
"YEAH! LETS GET THIS BREAD!"
let's get this bread refers to making money (because money=dough and dough=bread)
Ryan walked into work and greeted his buddy Jacob by saying ¨Yoooo!!! Lets get this bread¨
so wait the saying "get that head get that bread and leave" refers to getting stimulation to the male reproductive organ using the oral cavity usually to reach climax most refer to as "cumming" and then proceed to collect "bread" or the currency used in that place in the world that usually holds value in the stuff you are able to acquire with it, and then proceed to leave the (usually other sex) partner for an undisclosed reason.
He really did get that head get that bread and leave?