fill somebody in on something

He'd never got around to filling in his sister on the mission parameters.

If only we had something or someone to fill in on the third platform.

I've only met him once or twice before, when he was filling in on the day shift.

Eventually he was allowed to fill in on the air, reading commercials and the news.

This new man had been sent over to fill in on short notice.

Seeing no positive results, they recruited a friend to fill in on bass for the purpose of playing shows.

Where's your bit of paper then you have to fill in on this?

Chris Gentile has since then been filling in on bass.

After all, they're only really interested in having something to fill in on their reports.

No, I am not going to fill in on your cricket team next month.