How to explain the dialect "Jieshou = Go to the toilet"

The word "Jieshou" comes from the great immigrants from northern China in the Ming Dynasty. So far, Hebei, Henan, Shandong and other places say that going to the toilet generally follows this statement. Because the immigration of the Ming government was mandatory, officers and men tied the immigrants on the road to prevent them from escaping. Binding two arms is called big binding, and binding one arm is called small binding. Not only that, but I am also afraid that they will run away tied up, and the tied people will be tied together with ropes before being escorted to the road. Many people are connected and stop when they want to move. If a person wants to move, it involves a lot, and no one can escape. For the escorted officers and men, it is natural to save trouble, but for the bound immigrants, it is hard. The most troublesome thing is defecation. In order to express the meaning clearly, it is a long story. For example, if a person wants to defecate or urinate, he must first report and say, "Please stop, please untie my hand, I want to urinate." The more people there are, the more times the rope is untied on the road. Officers and men also feel trouble, but this method can't be changed. Then only a few words can be simplified: I want to untie my hands. The listener can understand. Until later settled down, this expression also became an idiom and became synonymous with defecation. But there is still a saying that big hands and small hands are untied, which means defecation. I don't know where this came from. For the word "convenience", Gu Ming thinks that convenience means convenience, which has a general meaning and it is difficult to make a single explanation. Besides going to the toilet, many other things can also be called convenience. For example, we often hear people say that "to facilitate others is to facilitate ourselves", which is a term in our life. I can't walk any further. I want to ask the driver to give me a ride. "Convenient, give me a lift." The driver said, "OK, OK, come on up." This is also convenient. Instant noodles can be eaten with boiled water, which is also called convenience, internal urgency, and convenience in going to the toilet ~ ~ all for the same reason!