avoiding eye contact with an aquaintance in a public place.
I saw my fifth grade math teacher at Denny's and head-downed him because I didn't feel like talking.
when a person is so tired they just want to retire to their bed and get some much deserved sleep
'i just wanna get ma head down for a square 12' and 'i got my head down for a square 12 hours'
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.
man my friend said something so gay so i made him put his head down.