A polite way of sexual expression directed towards any female with a big ass that is typically mumbled to ones self or in the proximity of a fellow perv.
Craig: Damn. Look at her over there
J Love: Awwwrightttt!
Craig: She's keeping it THICK.
J Love: She's keeping it REAL.
Craig: She's keeping it REAL THICK!
J Love: Hell ya!
Originated from the US Marine Corps in the Vietnam conflict calling for the Sikorsky H-34 helicopter. Since it was not used as much and was readily available in the war, Marines called for support and evacuation with this slang.
After the conflict, sometimes US Marines use the saying to state a request for assistance.