Ji Jing 擠勁 this is the third energy. Ji means squeeze together, like people in a bus or in the Tube during rush hour, when it is too crowded people squeeze in together. So Ji Jing is squeezing your opponent, to make them lose their balance by pushing them.
Ji Jing is pushing with two hands crossed together, which you can see in Tui Shou推手. We use both palms either one palm in and one out, both palms out or both palms in. As long as we push with two hands crossed together this is Ji Jing. When we push out with two palms crossed together it also involves Peng Jing掤勁 as any power which comes from inside to outside is Peng Jing.
Ji Jing is very powerful if we know how to use it well. During Tui Shou once our hands are crossed and we feel close enough to opponent’s body then we can use Ji Jing. It takes practice and eventually we can master it.