Well for a little background info - my DS6 seemed to be left handed prior to entering preschool. We kept telling them he favored his left side, his Dad was left handed, he bats left handed, etc. Well they continued to push his right side telling him he was holding his pencil in the wrong hand at preschool, etc. Fast forward - he is now in Kindergarten and struggling with his handwriting. Any suggestions on helping him overcome this obstacle? During all of this time we work with him and have tried to get him to use his left hand but he would tell me that is not the way his teacher told him to do it. Now he is more comfortable holding his pencil with his right hand but doesnt have good control and his handwriting is horrible. Letters big and small and all over the place. The teacher told us to get some modeling clay to help him improve his motor skills. I am going to try this but dont see how that will help his handwriting and control of his pencil. Any other suggestions?
No advice...just hope he overcomes this obstacle! 

I can't imagine ever doing that with one of my students.
maybe if he writes w/his left hand at home and show him if his left hand writing is better, it will give him the encouragement he needs. good luck!