Slang term, means someone needs to change their behavior as they are acting childish.

Running for exercise and picking up trash you find along the way. It's good for the body, mind, soul, and environment! Started in Sweden but is making its way to the U. S.

Something you would say to most users in Urban Dictionary

A phrase parents use against there children, who were a lot more fabulous and fun than they were

Something somebody doesn't have to do if they have reached a certain age and haven't done so already.

That thing you've got a whole lot of to do.

Grow up is phrase said to people who are acting like a bit of a chump and need to act their bloomin' age.