Mouthing is when babies and young children use their mouth to explore and learn about the world around them. They put things in their mouth, like toys or their hands, so they can feel and taste them. This is a normal part of their development and helps them learn about different textures and tastes. However, it is important for grown-ups to watch them closely and make sure they are not putting anything dangerous in their mouths, like small objects or chemicals. As children get older, they usually stop mouthing as they develop other ways of learning about the world around them.