Why can porridge in Guangdong be described by a telephone?

In Guangdong, people who describe the "one-time talk time" on the phone use "porridge" to describe it: "telephone porridge", which means a bit of ridicule and comes from Hong Kong. "Porridge" needs a lot of water, and it takes "a long time" to cook rice until it is rotten and thick. "Boiled porridge" is a Cantonese dialect, which is equivalent to "boiled porridge" in Mandarin, but "porridge" is thinner than "porridge" and not so thick. This is common sense. If porridge is cooked for a long time, the water will evaporate and it will not be cooked into rice. Any dialect will be close to common sense, describe things properly and will not be confused. The first step of "porridge" is to put a lot of water; If you put a little water in the first step, it is "cooking", not "cooking porridge". The difference between "boiling" and "cooking porridge" lies in how much water is put in the first step. If you put more water into "cooking porridge" than "cooking rice", it becomes "porridge", but there is no such word in "Cantonese". "Rice" is cooked rice or soft cooked rice. "Porridge" is very thin, and water accounts for most of it. If "rice" is cooked into porridge, it is called "rotten rice" in Cantonese, and most Cantonese people don't like it! ! ! In the eyes of Cantonese, there is only the difference between "rice" and "porridge".