An abbreviation for chinese slang "Ai Si Bi Ba". “Ai Si” is the
pronunciation of "S", "Bi" is the
pronunciation of "B", and "SB" is an abbreviation of “shabi” (that means "stupid"). "Ba" just expressing
exclamation. "Ai Si Bi Ba" basically means "are you stupid?". It‘s generally used for joking each other between friends, rather than really scolding and yelling.