[rkou]

Place your hands on the back of your head, with the fingers interlocked, and the thumbs pointing down gently pressing/rubbing on your neck.

Slowly move your eyes to any fixed direction (say, to the right) and keep your eyes open, staring to the right.

This will initiate a yawn or deep sigh in most people, stimulating vagus nerve.

[kvgr]

What kind of sorcery, i tried this and yawned within second.

[wincy]

Interesting, another poster called it sorcery but I tried it three times and nothing happened.