Snorting a mixedline of oxycontin and cocaine, that you setup before you passed out, as soon as you wake up in the morning.
Me: Hey you seem pretty relaxed this morning You: Yeaaaaaah brah, I woke up and rode the coaster this morning.
Me: I think your nose is bleeding....
You: Riiiiiiiiight on.
This is the phenomenon that occurs when you see a ridicuously hot chick that makes you instantaneously pop wood, blow your load, pop wood, blow your load, pop wood, and so on. Similiar to the peaks and valleys one would experience on a roller coaster.
"Dude, you see that chick in the mini-skirt? I'm totally riding a boner coaster right now."
The Funniest roller coaster out there, that jsut so happens to be so funny that you must combine the words rollercoaster and lol to get the meaning across