Air Conditioning - Temporary Solution?

I own a Haier HPR10XC6 Portable air conditioner unit which up until this year had given me no problems whatsoever.

While moving to a new apartment I had lost the drain plug to this unit and quickly found that attempting to run (forgetting the plug was missing) resulted in a wet mess. I put in a service call to both Haier and as a result apwagner and after waiting the quoted 2 weeks was informed that because of world events I may be waiting until September to get this small inexpensive part. I broke down and put in an order for an identical model intending it both as a gift to my parents so they would not have to continuously install/remove their living room unit every summer and for plundering the plug until a new one arrives. I am now wondering if there may have been a simpler more inexpensive way to go about it although my father seemed convince that the missing part was specifically made for this unit and that no other stopper of any sort will do. Had thought I could hook up a drainage hose to a tank as a temporary measure but he remains insistent that the hose would not be water tight.

Any ideas? I'm open to temporary solutions of any kind.

Without a picture, can not see how the plug works. but since it is a very small amount of water, any hose and/or pan will do if you can catch it. Or put something direct under it will solve your problem.