above...
(edit)holla = hollar (i.e., yell)
that is, say "What's up" to him
(edit)
Ooops, yes, it's spelled holler as noted in one of the answers above...
(edit)
"I'd like to give a shout-out to all my homeys. Holla' back, now!" LOL
"I'd like to give a shout-out to all my homeys. Holla' back, now!" LOL