I didn't know about this term until very recently when I was showing a couple of my fancharacter artworks for a specific media to a friend of mine, explaining how I tried to insert their lore into the canon, and she just went "oh, so you got some yumeshipping!" XD
I could join soon, at least as a way to show some of my projects I usually don't feel like mixing with my main ones. I come from a time where self inserts, even non-romantic ones, were very looked down upon so for the longest time I kept low with them, but I see they are resurfacing lately without the old veil of self-shaming that was felt before, so this gives me a tiny bit more confidence.