One is to add a little rice, and the other is to pay attention to cooking methods and utensils.

Method: After boiling, turn on a small fire and simmer slowly, instead of cooking all the time, so that the porridge cooked slowly can stick together.

Utensils: If you have a pressure cooker, cook it in a pressure cooker. The porridge is sticky and slippery, and it won't have residue like you said. If you are worried that the pressure cooker is unsafe, buy a rice cooker that can cook rice and porridge for 2 hours, and use the porridge stand for about 1.5 hours, and you can also cook slippery and sticky porridge.

I use millet+rice cooker 1 to cook porridge for my baby for half an hour.

In addition, millet is cool and babies should not eat more. If they want to eat, they should add something warm, such as a little brown sugar.

I say this because I see that your information is Wuxi and Jiangnan, and the staple food in the north is millet, because northerners eat more warm things, such as green onions, mutton and beef. So eating millet is nourishing and neutralizing the coolness of millet, so there will be no problem.