An acronym which stands for "Dance Floor Make-Out," an act commonly found at parties and clubs, particularly when alcohol is involved. It is generally sloppy and includes a large amount of P.D.A.
Common results of D.F.M.O. participation include: regret, shame, self-loathing, rejection, and public knowledge of your make-out affairs.
Did you see that major D.F.M.O. between John and Krissy at the party last night? They were so wasted.