[in the swim] {adj. phr.}
Doing the same things that other people are doing; following the fashion (as in business or social affairs); busy with what most people are doing.
* /Jim found some college friends at the lake that summer, and soon was in the swim of things./* /Mary went to New York with introductions to writers and artists, and that winter she was quite in the swim./
Contrast: OUT OF THE SWIM.