Lives: North Park
"Shralpin' on the gnar gnar," isn't really surfer slang, it's more like making fun of bad '80s surfer slang. I use that one as a joke when I talk about a day of surfing. Like "it was out there, brah. We were Shralpin' on the gnar gnar ." You have to use that dumb '80s surfer accent when you say it.
I'm into off-road racing and I'm building a Baja 1000 Jeep, so I know a couple good ones that revolve around racing. One is "bombin' it," which means you're not going too fast, but you're on the edge. Another one is an old racing term that means pretty much the same thing, "Wide open until you see God, then hit the brakes."