I'm plumbing the drain for a shower which consists of several short pieces of pipe and several fittings (Short pipe from the drain to a p-trap. 90 street el out of the p-trap. One foot pipe from street el to a 90 elbow. One foot pipe out of 90 elbow to a coupling. Coupling to a one foot pipe out of an existing sanitary tee.) I cannot see any sequence of putting these pipes and fittings together that will allow me to push and then also twist the last connection. It seems to me it is even going to be difficult to get the last piece in at all, but I think my best shot would be to glue the coupling last (assuming I can get the 2 pipes being coupled far enough apart to slip it in) and then to twist the coupling. I've also considered using a p-trap with union since the components are in an open area. Then I could connect the union last. Any thoughts?