This refers to a person who is wheeling with bottom of the barrel standards. The phrase refers to "Trolling" as when fishing, when one tries to catch bottom feeders by running a lure along the bottom of the lake. The "Slizz" part represents the scum that one will inevitably catch when wheeling with such low standards.
1. Damn, Luke hasn't gotten a chick in weeks. He's just trolling for slizz right now
2. Hey guys, let's hit the club and go trolling for some slizz!