What to do when another child bullies yours?

7 ways to deal with bullying between toddlers:

1. Tell your son to say to the other child, "That isn't nice. That hurt" 

This allows your child to state his frustration and voice out for himself, allowing the children a chance to resolve the conflict situation themselves. This gives the other child an opportunity to learn to apologize.

I have made a separate post on more to teach your kid to say with confidence and grace:

http://momlearnings.blogspot.com/2014/10/how-to-deal-with-bully-at-kindergarten.html

2. Use distraction

When you see conflict brewing, distract them by playing loudly with another toy or breaking into song.

3. Use "we" instead of "you" to correct the other child

Find a nice way to correct the other child, if you absolutely need to. Say, "no, we don't hit buddy", or "we have to take turns and share". Say, "it is not nice to push, but we can all play with it together". Don't say, "it is wrong of you to hit."

4. Help the children to cooperate

For example, if it is a matching game, and the other child pushes yours away, say, "it is not nice to push, but we can all play with it together". Then have the other child find one animal and your child find the other and make it a game for two. Go on like that for about 5 minutes. At the end, ask, "isn't it fund to share and play together?". Most likely the other child would say yes!

5. Encourage good behaviour

When your child's friend does manage to do something nice such as sharing a toy, tell him how much you appreciate his friendliness.

6. Suggest another location for playdate

Toddlers are more apt to feel fidgety and act out in small areas i.e. living room. Moving to a large open space such as a park or playground may help, as they can burn off excess energy and social frustrations withotu stepping on each other's otes, and there won't be any toys to fight over.

7. Take a break from the playgroup as a last resort

You aren't teaching your child anything by asking him to cope with a child who's mean to him. If the situation persists, your decision to separate the children might open up a dialogue between you and the other parent that could pave the way for a more long-term resolution.

2 basic rules to live by (if you can!):

1. Never tell another parent how she should raise her child.
2. Never discipline a child who's not yours

References:
http://www.babycenter.com/404_should-i-discipline-a-child-who-is-acting-aggressively-towar_11609.bc