Keep it under your hat?
602542
They mean in keep your secrets in your head.. you can´t expect others to keep the secret, if you can´t.
884028
Put a bag over your head
1063082
you need to keep it moisturised
252540
Wear a hat until it grows back.
635927
Well, it's getting near summer. The weather is warming up. Don't you think your helmet will be too hot? How 'bout just your cap?
1153069
Keep your mouth closed.
1061441
Only that you keep the string hidden so that no one knows you are wearing one.  Also, that you keep it changed often so that you don't have any leakage.  :)
320796
when in doubt, pull it out
736139
When you are inside take it off.  Not much simpler than that.\n\nUnless they serve a purpose such as shade, protection or keeping warm they are useless.  Why bother wearing it sideways, backwards or upside down ?  It only makes you look like a ridiculous dimwitted fool !!!!!!
827734
Yeah you should leave it there. Just for extra protection.
825289
You won me over the day you put that hat on.\n\nSo no...I don't want you to change a single bit...just want you to be at peace.\n\nBut, don't we all...
805577
where you put your briefs ^_^
835264
put it in your sleeve
229385
yes.keep your mouth shut.
582515
You can if you want.  It's weird, though.  I'd keep it in casual conversation and out of scholarly papers and the like.
357169
I suppose you wear it as a reminder?
942147
Keep it to yourself.  Its the right thing to do.