To produce a demonstration of the McGurk Effect. 

1. Grab two friends, you'll need three people.

2. Have an observer face you and keep looking at your face. 

3. Have another person stand behind you so the observer can't see their face. 

4. Begin repeatedly saying the word 'vase' silently, while the person behind you repeats the word 'base' outloud. It might take some practice. You can acheive synchronization by counting down 3, 2, 1. . .

5. After about 8 repetitions, stop and ask the observer what they heard. They should have heard 'vase'.

6. Now repeat the synced phrases, but this time tell the observer to shut their eyes after a few repetitions. 

7. With their eyes shut, they should hear 'base'.

8. The observer can try opening and shutting their eyes, and what they hear should change from 'vase' to 'base'.