R.K.
Don't back down. Most bullies are bullies because they are scared or it's what they learned at home. You can be gentle but firm and say NO. You can't have my lunch money or my cupcake or my place in line or the ball I am playing with but you can play with me. They also need to know they can tell. If someone is intimating them they can tell Mom, or teacher or playground supervisor, or principal and the bully will be dealt with.
And sometimes Mom has to yell. My daughter was being grabbed on the boobs all through 3rd grade and into 4th grade, finally she told. I called the police, a report was filed and the other child's parents were talked to and that mother got a case of the 'how dare she'. The harresment became verbal and Mom (me) had another talk with the school principal and that stopped but then the kid started making faces at her and just kept harresing her. I kept asking that they remove one or the other child from the classroom but they refused. It got to the point that I got really mad and told the principal that it stops NOW of I would walk into the classroom -- grab the boy by the shirt -- drag him to the window -- open the window -- hang him out the window -- and tell him to leave my daughter alone or I would drop him. You know it stopped. This was after about 6 months of continued harresment -- not including the 3rd grade year. ( That was my daughter's 4th grade year)
Fifth grade the TEACHER was the bully. Suffice it to say I scared that teacher so bad that even today 12 yrs later if he sees me he turns white and leaves.
I started out gentle but firm but this guy just didn't get it. I threatened to quit my job and sit in the classroom, all day every day, and if he ever raised his voice or physically threatened a child again I would take him out then call the police. He retired at the end of the school year, I still had one child in that school.
In other words don't put up with it.