Similar to LOL'ing when you see something funny online, you JOBOL when you see some totally hot barely legal or MILF material while surfing on a laptop... Put simply, you Jizz On Back Of Laptop.
Dude, did you see that picdump with all the amateurs I sent you?
Oh yeah, I JOBOL'ed while looking at that pr0n
I hadn't punched my clown for a few nights, and when I saw that new vid of Kim Kardashian I JOBOL'ed so much I almost ruined my laptop.