I have an ABS pipe fitting under my kitchen sink which appears to be held on by friction (white piece just above the p-trap). After the p-trap the pipe makes a long run to the left where it's not really supported by anything. It seems the weight of this run caused the pipe to slide down off the drain pipe, causing a huge gusher.
I'm not totally sure how this is intended to work, but it seems like the white fitting just holds the p-trap and everything on by friction? If so, what should I do - replace the white piece? Anything else? Also, how do I know what the correct height of the fitting and slope of the lateral pipe should be. The lateral pipe was fairly level before, but a friend noted that ideally it should slope a bit. Not sure if I'll mess anything up by adding slope.
(Note: zip-ties in the pic are my temporary safeguard).