Watch the The Robert: Back to G online guitar lesson by Stephen Mougin from 30 Bluegrass Runs You MUST Know

The next few runs will get you back to G from either C or D if you're in the key of G. Sometimes, during a jam (or whenever a fellow musician doesn't know the song), it's helpful to "direct traffic" a bit and show folks where the chords go. This is a nice way to return to "G".