I haven't tried this, but I've seen other people say they transfer a little ink to an ink well and add a thickening agent of some sort to help. I just dip straight into the bottle, just be sure to get it at least over the hole in the nib.

Though I haven't really had that problem with my Hocoro dip pen unless the ink is super watery. Even then it still works just have to re-dip frequently.

I swatched all of this past Colorvent with one of those dip pens (stub and EF nib) and it went well.