I usually DM for our group, but another guy wanted to try... is it possible for me to make him the DM of one of my campaigns in DDB, given that I have the subscription?

I can't see a way to do it in the UI, so I kinda assume no, but figured I'd ask.  It would be nice if we could reuse my sub for his game.

If you join his campaign you can turn content sharing on.

So if I have the DM subscription, but he's the DM and I'm in his campaign, we can content share?  That would be awesome.  I guess I should have tried that first :)

You can't change the DM of a campaign, but content sharing can be enabled by a player with a subscription (my group does this).