Instead of using slang already established by other rappers, why not go for your own styles and improvisations? This is in essence what they're doing anyway. Set the curve; don't underestimate people's cleverness and don't under-assume yours--meaning don't try and work with very obscure relations, but find that Goldilocks zone where your images affirm as well as surprise.
(Really this applies to all poetry)
Run with context like a sparkler, and your words a long exposure camera.
Here's one I did for a prompt thread, to show you how to have fun with your words and not be afraid to make some up if you know they're well within the established context:
Wait. Wait and see, patiently.
See the sky: Sea of sky -wait-
si, a cloud. A cloud or two.
Adrift in sea of blue. Wait.
Too, see land. A seashore line.
Where green and blue combine. Wait.
Hear soft-stream skysea flowing,
blowing over fir and -wait-
skin; waterfalling down to
horizontal landlakes. Wait.
Taste the moonsugar blending
with skyriver's kiss. Await
refreshing bliss from sip
of lung this rushing rill. Wait--
unroot--de-weed floor of feet.
Carry up the current, wait,
and brave the deep which turns to black.
Patiently, just see and wait.
Blended sugar then turns salt
which glitters in the dark. Wait
through pain from salt-in-wound to
see the sun, and moon, await-
ing simultaneously
those patient enough to wait
and wade the sea to see.