Getting the dirty water out of your system

Then the clean water can flow.

Ed Sheeran on songwriting: “When you switch a dirty tap on, it’s gonna flow shit water out for a substantial amount of time. And then clean water’s gonna start flowing.”

Same with comedy. You're gonna write shit jokes at the beginning. And then you start flowing better bits. And then the jokes get better and better. So you’ve just gotta get the crap out before you can move on to the good stuff. Same with gigs.