How can I leave a hickey on each other? Urgent! ........

Just like an ordinary kiss, it only covers a small area, and then it keeps sucking hard, creating a vacuum. As long as the place is congested for a short time, it will form a hickey. If you ignore each other, you can also gently bite that place with your teeth. It won't hurt when you bite, but it will hurt a little because of the air pressure, but it's not very severe.