Don’t try to open your cat’s mouth when it is riled up, playful, or upset. You should also avoid waking your cat up to open its mouth, as it could scare the cat. Instead, just pick a time when the cat is calm and happy and wants to be around you. You need to think about where and how you will hold your cat and how and where you will hold any medications you are going to give it, if you are doing that. Ideally you will do this on a tabletop. Make sure there is nothing breakable nearby on the table, as your cat may break loose and knock things over.  Place the towel or blanket on the table and spread it out. You will use the towel or blanket to wrap the cat up so it can't move. You will also want to have a syringe (without a needle attached) full of water on hand if you are giving your cat a pill. This will help to wash down the pill. Keep the pill in your more dexterous hand. Get your arms at the same height as your cat. Pick up the cat and place it in the middle of the towel, holding it down in a prone position on its belly. Bring one side of the towel up over the body, then bring the other side up over snugly. Bring the back end up towards the front making sure it’s snug.  Finally wrap the front of the towel around the cat’s back snugly. This should only leave the cat's head sticking out. Make sure the material is snugly wrapped around the cat in order to keep legs and claws inside the material. Try and calm the cat if it is fighting you. Some cats will put up with being wrapped up extremely well, while others will fight you tremendously. Gauge your specific cat and judge whether you can wrap it and calm it down or if you just need to wrap it up right before you open its mouth.

TL;DR in Vietnamese:
Lựa chọn thời điểm khi mèo đang thoải mái. Xác định tư thế của bản thân và thú cưng. Đặt mèo vào vị trí sao cho thật thoải mái.