Do you have places that need some work done in your manuscript?
Do you mark them with "insert spiffy episode here"?
Do you use "insert" to flag things that aren't finished?
A word to the wise: search for all instances of "insert" in your sample pages and your manuscript before you start sending it out. It's not a deal breaker, but why look like a nitwit who can't read if you don't have to, right? (insert pithy remark here).