To keep something under your hat means to keep it hidden.
It means don't tell anyone -- keep the news to yourself.
Don't need to advertise. Be casually discrete; just keep "it" with you (so to speak). And go about your way.
"Keep it under your hat" means don't tell anybody.
It means for you to keep your hat. Perhaps you are thinking of "keep this under your hat," which means "keep it to yourself" or "keep it secret." The image is of someone hiding something beneath their hat, on top of their head, where only they know it's there.
Tell me dear brother What's driving you mad Have you got the answer I'll keep it under my hat This working frustration Get it off your chest There's no motivation A chance to get a rest Mechanical feeling Why there's is no such thing A human endeavor Has got the truest ring No need to get angry Who wants to do that So tell all your secrets I'll keep it under my hat I'll keep it under my hat I'll keep it under my hat I'll keep it under my hat Under my hat Tell me dear brother What's driving you mad Have you got the answer I'll keep it under my hat No need to get angry Who wants to do that So tell all your secrets I'll keep it under my hat Yes I will I'll keep it under my hat Right down under I'll keep it under my hat Its so right I'll keep it under my hat Under my hat I'll keep it under my hat Under my hat I'll keep it under my hat Under my hat I'll keep it under my hat Under my hat I'll keep it under my hat Ooooh down under my hat Right down under my hat I'll keep it under my hat
keep it under your hat
Literally, this is going to be a fast, rough ride and your hat will blow off if you don't hang on to it. Figuratively, we're going to do something fast with few precautions.
It means that the more information you have (and keep to yourself), the safer the other person will be.
keep it under the hat
It means "Don't tell anyone."
Charlotte Mary Yonge's novel, Nuttie's Father printed in 1885 portrays the first known usage of this phrase. It means "keep it in your head or keep it secret."
to keep his hair under control while fighting
his head : ) I think you mean the bandana.
Maybe "Flat tire", since the letters are short and wide.