demonstrator

noun7

1. •
   One who demonstrates anything, or proves beyond doubt.
2. •
   One who takes part in a demonstration; a protester.
3. •
   One who demonstrates products in a retail environment; a merchandiser.
4. •
   An assistant to a lecturer.
5. •
   One who teaches anatomy from the dissected parts.
6. •
   An item, particularly a vehicle, used in demonstrations to a customer or user.

   • Young people have been involved in choosing which resources and educational toys are used to deliver sex and relationship education – including leaflets, videos and condom demonstrators. — 2006
7. •
   The forefinger.