Play Pipa is a technique that appears twice in the Yang style 108 form. Below is an extract from a longer video of Grandmaster Dong Huling showing its application in push hands.
The pipa is a Chinese musical instrument, somewhat like a guitar, but with 4 strings and a pear shaped body. Below is a picture showing how the pipa is typically held when played. Does it not resemble the way GM Dong applied the technique?
GM Dong’s video shows the way the Play Pipa technique is normally executed on the opponent’s outside position. For beginners this is a safer position to apply the technique without having to worry about the possibility of the opponent trying to punch you with the other hand.
However, our point is that a technique should as far as possible be able to be applied even when we are standing in the front gate of the opponent’s position. To safely use Play Pipa and not be punched we need to address the elephant in the room by examining the use of strategy. In this case the strategy is to distract the opponent before we apply Play Pipa and for this purpose we are borrowing a move from the Fast Form as shown below :-
The video below gives a more detailed explanation of how the use of a strike to distract can also help you to land the position :-
And it goes without saying that once you get the arm locked you should use proper leverage to jack the opponent up and away.
For the purpose of learning we did not include those parts of Play Pipa that can cause injury.
Reference – The leverage principle is explained on page 68 of TaijiKinesis Vol 2 : Learning the Taijiquan Form. The part of the application that can cause injury can be seen on page 336.