Forcing children to share usually does not work
Why? Forcing does not encourage them to share on their own. Making a child share often means that you take from one child to give to another, and the child is now unsure when something will be taken away from him or her. The result is that children hoard things instead. Give children choices, “would you like to play with the red cups or the blocks?” so they can choose what they want, this can be a way to avoid hoarding.
The best way to teach sharing is to be generous yourself. Here are some other tips from Susanne Ayers Denham a Developmental Psychologist with babycenter.com:
Take every opportunity to show your host child how to share. Offer some of your meal or a chance to assist in the fun of decorating a cake. As you do, use the word “share” to describe your behavior. For example, “I’m eating a really good sandwich, and I’d love to share it with you. Would you like some?”
When a toddler attempts to share, praise those efforts. Little by little, he or she will notice the positive reinforcement and feel good about repeating those actions. Before long, sharing will start to come naturally.
Never punish a child, especially a toddler, for not sharing. You can let the child know you’re disappointed and sad when he or she doesn’t share, but that’s it. Don’t make a big deal out of it.