The act of exploring a cave, or caves for entertainment. Often referred to as "Cave Diving"
I am going sperlunking next week in some remote areas.
It's called spelunking you dip shit.
When you add words to urban dictionary like sperlunking, you should make sure you got it spelled correctly moron.
(verb) to cuddle with your HUNNY; to get close to each other without having sex; to take a nap together
Dan: I'm sleepy
Amanda: Wanna sperlunk, hunny?