"Ha ha get it? I'd probably visit where Katrina hit And damn sure do a lot more than FEMA did" the lyric is missing from your question but I think this is the part you are talking about. Katrina is Hurricane Katrina. A hurricane from 2005 that devastated large areas of the south eastern United States. FEMA is Federal Emergency Management Agency. FEMA is a government agency that was in charge of helping people hurt but Hurricane Katrina. There is lots of criticism of them not helping people well. He is saying he would help people more then FEMA did.