That is playing the tongue, which is a skill in rap music. The reason is that continuous syllable pronunciation can be pronounced continuously. This syllable-clear "continuous reading" is called "tongue-licking" because it feels like the tongue is "tongue-licking". The practice method of playing the tongue is 1. Speaking speed and improving speaking speed are the basic conditions for touching the tongue. Remember to pronounce clearly, don't play with your tongue just to play with it. 2. After practicing speaking speed, here is the feeling. Generally speaking, when learning a foreign language in China, the feeling of playing tongue sounds is to look for it with half a glass of water in your mouth, which we can learn from. Everyone has several sounds that are good at playing the tongue. Such as "R", "N" and "L", find the sounds that you are good at playing the tongue and practice more. G-Dragon likes to use this skill very much ~