Hi,
A little boy in my son's class had this habit and I was very concerned that my son would pick up on it. They treated it as part of his behavioral plan and, thankfully, the boy stopped doing it. Maybe this will help you:
Don't acknowledge the spitting in a negative OR positive way. In a calm manner, (easier said than done sometimes

require that every time she spits that she get a tissue (have boxes nearby but not too close- you don't want to make it too easy for her)then SHE must wipe her mouth and throw the tissue in the garbage. Eventually the spitting was not "fun" anymore for my son's classmate because it required some work behind it.
Hope this helps you.
------------------
Leslie, Mom to Tristan 6 autistic and Lucas 8 NT
[This message has been edited by LeslieC (edited 07-02-2003).]