Banging rocks could mean "screwing / fucking around" (being stupid while not doing anything productive)... although this isn't universal slang so I don't know.
Between banks is probably literal.
(Bank has 2 definitions, 1 is geographical the other is a structure)
"Feet kicked up" is a body position when you are sitting in a chair or seat and your feet are on a table or other surface.
It can mean figuratively "to be relaxing" although again, not universal slang.
The last one I cannot tell you.
Slang is different from region to region. I live in a "ghetto" environment in California, USA (one of the GTAs took place in this state) and the slang I know isn't like this.
The large cities have their own slang.
But if you are wondering about if this is general US slang, street English or a universal dialect such as AAVE or chicano English.. the answer is no...