Meaning/Usage: Commonly used to tell someone to stay in touch 通常用来告诉某人保持联系

Explanation: This is commonly used when you are talking to someone you don't meet or see often.

"It was really nice seeing you again. Don't be a stranger."
"We need to keep in touch. Don't be a stranger."
"Now that we live so close to one another don't be a stranger."

A. "Hey John, I don't see you around here these days."
B. "I moved down south several months ago."
A. "Keep in touch man. Don't be a stranger."
B. "Definitely. I'll buzz you every time I come up."

Other Common Sentences

"Keep in touch."
"Ping me once in awhile."