Mice can be tamed and bonded with easily if you use food. Start by simply spending time near your mouse’s cage. Let your mouse get used to seeing you often. Talk to your mouse when it comes out of its nest box.
When you reach your hand into the cage to give your mouse food, watch to see if it darts away and hides. It probably will at first. Eventually, the mouse will learn that the presence of your hand means something good to eat. The mouse will begin to stay put when you reach in to give it its food. Once this happens, try offering some directly to your small pet from your hand. If the mouse runs away, it is not ready. Try again in a couple of days.
Once your mouse takes food from your hand, try luring it onto your hand with treats. Once your mouse takes the food from you and sits in your hand while it eats it, you have successfully bonded. In time, your small pet may even start running up your arm to sit on your shoulder.
Eventually, you can encourage your mouse to retrieve food from your shirt pocket while you are sitting down. Show it a treat while it’s in your hand and lure your small pet to your pocket with it. When your mouse is close to your pocket, drop in the treat and encourage it to look for it. After a few sessions, your mouse will quickly learn to retrieve the treat.