There is a somewhat little known, but simple way to lure blobs. It works regardless of your profession.
Once you're in the right place, after going down and noticing that there are few or no blobs, go up again and stay there for a few seconds.
On the first or second attempt, the blobs should already start appearing on the screen.
You may have to repeat this process a few times, but nevertheless it's very quick and you don't have to struggle with proper summon placing, or stay there a few minutes waiting for all blobs to appear.