I believe in including humour, both in the services and the sermons. If I’m going to poke fun at anyone, it would be at myself. Making fun of another person, whether a family member or someone in the congregation is not appropriate.
But there is a limit at how far to go. I know of a Christian leader that I respect very much. He has a lot of wisdom and insight to share. However he is also putting himself down, presumably in an attempt to be funny. In moderation it would be funny, but consistent self-deprecation can become distracting.
I will joke about how bad I sing or how much I love potlucks or my lack of hair. However, I don’t really make fun of myself or describe myself as stupid, even for a laugh. There is a fine line as to how much pastors should poke fun at themselves.
Do it enough to show that you are human and have a sense of humour but don’t try to destroy any sense of respect people might have for you.