M.R. Share definition Flag masterbation race. Typically when your girlfriend is ragging out and you cannot have sex. You want to aim for a tie. I was having a M.R. with my girl, and I won all over her face. M.R. by Gabbangtiffalicious November 29, 2011 0 0 Get merch Get the M.R. mug. Buy Now — $32.95 See more merch