1 definition by Cam Bomb
short for 'Massive Sperm Buildup' - usually occours in young male adults under 25 as a result of no sexual activity for more than a week or 2
Derek had not masturbated for about 3 weeks and was suffering from a severe case of MSB, but after watching 5 minutes of crazy cumshots #4 he had a massive sperm bomb and had to use his blue bandanna to clean up!
by Cam Bomb February 19, 2012