If there's not an entry on Urban Dictionary, and I've never heard it used, I am not sure it even exists in anything resembling widespread usage. There's another thread in the IT-EN forum at the moment talking about "boom shanking," but I don't know what that is either, and neither does Google. Nor does Google know about "boom shaking."
You didn't give us any context i.e. where you heard it, who said it to whom, when and where etc. However, there is a hip-hop song called, "Boom, shake the room" by Will Smith. The title is from the chorus, ending with the line, "Tic tic tic tic boom!" It may be a phrase coined by pot smokers to express a marijuana "high" which if excessive can cause an adrenalin rush - hence shaking.
It's the first thing that came to mind, so don't hold me to this theory.