Another way of applying the handspawning technique (apart from breeding), is to prevent egg congestion in your female fish. Congested eggs will lead to spawn binding is a very deadly ailment which can kill your female fish if their eggs are not able to release. I lost 1 of my favourite ranchu to this before.
Below is a video on applying the 'rubbing' technique on how to get her to release her eggs. I'm using my white ranchu after noticing she's been chased around by the males, a day after I did a major WC.
Apologies if the video or my demonstration wasn't too clear. The eggs should ooze out quickly. Noticed from the video the eggs been released and floating around in the tank? This is what I got in the end.
My advice is: Make sure your female fish has eggs first. You can tell from their abnormally huge or sagging tummy. Just a gentle rub and do not squeeze her tummy or else you won't know what else will come out!
Please go easy on your fish and don't overdo it. The fish will be stressed out. Return her to the community tank once it's over.