Mutual Submission In A Christian Marriage

What is mutual submission, and does it apply to marriage? Does Ephesians 5 teach mutual submission in marriage? What does mutual submission look like in practice?
This week on the Straight Truth Podcast, host Dr. Josh Philpot talks with Dr. Caldwell about submission. The discussion pertains to Ephesians 5 and centers primarily on verse 21. But of course, it can't stay there because Paul goes on to give further instructions for how this is to be lived out in other relationships. One of those relationships is marriage. Dr. Philpot says that it seems to him, in Ephesians 5:21, there is a kind of mutual submission taking place, which then moves into the marriage relationship in the following verses. So then, he asks, does Ephesians 5 teach a kind of mutual submission in the husband-wife relationship as verse 21 says before these verses?