Following a stupid comment the person who said it must bend at the neck and look at the floor. thus putting their head down in an act of shameful embarrasement. After this the person cannot be made fun of.
Acronym: Head Down Mother Fucker! Typically used to indicate that either oneself or the recipient should put their head down and do some work.
Worker1: So worker2 how was your weekend?
Worker2: Good thanks. You?
Worker1: Oh fine. Hows the kids?
Worker2: Yeah prettygo-
Boss: Head Down Mother Fucker!
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.