Between you, me and the gatepost
Definition 1 of 1
Pro Tip 1/3Secret Keeping
Use the phrase when sharing information that should not be spread or discussed openly with others. 
Between you, me, and the gatepost, I'm planning to propose to her next week.
Pro Tip 2/3Emotional Trust
Conveys a sense of trust and confidentiality to the listener, suggesting they are privy to sensitive information. 
Just between you, me, and the gatepost, I might be losing my job soon.
Pro Tip 3/3Not Public
Signals that the topic is not for public knowledge and helps to build intimacy between speakers. 
Between you, me, and the gatepost, the company's numbers don't look good.