It's basically a combonation of different positive adjectives used to describe someone. Like awesomely-amazingly-super-freaking sweet-person ever.
Like Derek Lee aka Bomb-Shiggity Derek
Chris: Hey Derek, can I borrow your english homework?
Derek: Yeah dude! Fo sho!
Chris: Well, you're white so you can't say that, but you're still the Bomb Shiggity