Bolliger & Mabillard, roller coaster manufacturers. B&M coasters offer a very smooth ride, and the characteristic roar caused by the polyuthereane wheels on hollow track.
B&M is so called because of its founders, Walter Bolliger and Joseph Mabillard

Examples of B&M coasters include: Nemesis, Oblivion, Mantis, Raptor.
OMG that B&M was great! How do I know that was a B&M? By the characteristic roar! Did I mention I'm a rollercoaster enthusiast?
by Johnj April 24, 2006
Also an acronym for bowel movement. Used in in assisted living or healthcare environments typically.
Did you record the time of his last BM?
by CJ August 12, 2003
Black and Mild. A pipe tobacco cigar sold in the tip cigarillo form. It has a nutty vanilla scent and a pleasing aroma.
Go in, get Johnny a pack of Camels and get me a couple B&Ms
by 0m3rt1 October 3, 2005
v. Bitch and Moan. When a person can not stop voicing their opinion after losing an argument. Could also be bitching and moaning.
God!! We told you that if you told another lame joke we'd tie you up and put you in the trunk! Stop all yer
B&M(ing) you little girl!!
by EviLalDo August 5, 2005
Bolliger & Mabillard - rollercoaster designers famous for fast, smooth, twisted track with the characteristic ROAAAAR! sound, caused by polyurethane wheels. Affectionately referred to by coaster enthusiasts as "Beamers".
Check out that new flying B&M that Six Flags New Jersey just built!
by Sarabellum1976 September 4, 2003
Abreviation for Bowell Movement (Verb I guess) Certainly not to be used anywhere near to "yo baby's Mama" and one poor sole has suggested.
Eating a balanced diet will result in healthy floating B.M's; not the bowl stanging sinkers most gangsters coil in dimly lit, fetid tiolets.
by Priz Biz Sage June 10, 2005