Abbreviation for bull shitting. Usually the slang term for bull shit is “bs”. So bsn is bull shittIN. It makes perfect sense.
by Erikboyz December 5, 2020
Get the BSNmug. by iBJocking February 28, 2012
Get the BSNmug. by Bigbootyjooty June 9, 2018
Get the bsnmug. BSN are da Hottest younng Niggaz in town an yall cant Fuk wit dem theyre also known around Texas an very popular but get straightt to da moneyy Kuz dey known to Finesse!!👿👑
by BSN da GaNg February 7, 2019
Get the BSNmug. by a.trae11 March 14, 2018
Get the bsnmug. 
