M.B.S.W.
It stands for; Must be smokin weed! Someone who was doing crazy shit while under the influence of weed.
*Zoe* Did you just see what the kid was doing?
*Tabitha* Dudeee that kid M.B.S.W!
*Zoe* Yeah, He must have been!
M.B.S.W.
*Tabitha* Dudeee that kid M.B.S.W!
*Zoe* Yeah, He must have been!
M.B.S.W.