To dream of spit or spitting represents feelings about behavior that seems insensitively aware of itself not being caring. Intentionally showing other people that you don't care about something.
Example: A woman dreamed of seeing someone spit using a pole to bang the inside of a bucket and then spit in the bucket when they were finished. In waking life she felt that her last sexual experience with her husband was empty. The spitting in the bucket at the end may have reflected her feelings about how empty it felt to have her husband ejaculate in her like it didn't matter.
*Please See Saliva