Peng, Lu, Ji, An
Literally - ward off, rollback, press and push.
From Tai Chi Forms in the section called grasp the bird’s tail or grasp the sparrow’s tail.
The following videos are from a Chen Style master.
And a blog post from Graham Barlow probably going in to more detail than I probably wanted!
https://thetaichinotebook.com/2015/09/10/peng-lu-ji-an-grasping-the-birds-tail/
