1. Air tight toilet pump. 2. Fill up the with water first 3. Use sudden force to push in. 4. and STAY for 10 seonds. !. This is important. Most people push and suck too fast and this does NOT work.
5. Pull with sudden force. STAY. 6. repeat push and pull. Remember to stay after each action.
I have been doing this for many times since I learnt the technique from 'si fu'