How do you react if you see your child being "bullied"?

First off, "bully" is a strong word - my son,an only child is 14 months old and it was a little shove. I am totally accepting of the reality that kids will be kids.Background- today we went to a toddler group at the local library weve been attending for about a month and socially my son is still quite excited at seeing so many kids in one place. On 3 or 4 occasions I see this boy abit older than my boy (maybe 2 or 3yo) watching my son and walking over to intentionally push him over (im on the other side of the room when this happens). My son giggles but pays no mind, its not a big push. This kids mother is busy with her younger baby so either doesnt see this going on or cant quite do anything to stop her son.Weve been in situations before where obviously kids accidentally knock each other over, but this situation is the first to genuinely annoy me because this kid seemed to make a beeline for my son with the intent to push him.Im asking for my own future sanity if/when this happens again - both if my son is being pushed or vice versa, doing the pushing - how do you react? You obviously step in at some stage (when?), but how do you do so as not to create awkwardness especially if you want to keep going to a certain group? I hate confrontation and dont want to be telling off other peoples kids, but as my kid gets older i dont want my kid thinking its okay for others to push him or to push others.Any words of advice or experiences is appreciated. Thanks for reading, apologies if i seem to be reading too much into this. via /r/Parenting http://ift.tt/2uI8bIh