Constantly needing to leave the room

• Allot specific times to get a drink of water.
  Examples:
  
  "You can get a glass of water after 30 minutes of work". Set visual timer to 30 minutes.
  
  
  
  "You can get a glass of water after completing 3 steps on your schedule."
  
  
  
• Specify days when the student can perform errands.
  
  
• Clearly outline the expectations. Do not negotiate with the student about leaving the room (excluding emergencies).