Between you, me and the gatepost British spoken informal
The word "gatepost" could be replaced by the word "bedpost".
Used for saying that what you are going to say is confidential and should not be told to anyone else
I want you to keep this information between you, me, and the gatepost! Could you do that?
Well, between you, me and the gatepost, I cheated on the final exam and the teacher knew nothing about it.
The room you are currently in.
To be secretly working together
Kept in secret
When two individuals desire to be alone with each other, a third person is not welcome.
This expression dated from the 18th century and appeared in the book Eugene Aram, in which a character tells a secret by saying:
“Between you and me and the bed-post – young master’s quarreled with old master.”
To be very wet
Because of forgetting bringing an umbrella, I look like a drowned rat when it rains.