When a person sulks in anger, it is really anger itself. For example, if a husband and wife quarrel intensely in the night, so much anger is generated that they both lay awake restless, the entire night. In the morning the wife serves him tea by banging the teacup. The husband will then realize that she is still sulking. This is called anger. The sulking can last for any period of time. For some it may even be life-long. Sometimes anger between a father and son will create such enmity between them that neither of them will want to see each other's face. The sulking is apparent from the disgruntled look on one's face.
Sulking can be such that, if someone were to insult me fifteen years ago, and I encounter him again today, the moment I lay eyes on him, I will remember everything from the past. That is taanton (the lingering connection from the past event). Ordinarily people's sulking never goes away. Even renowned ascetics and monks sulk. If you were to provoke them and challenge their authority, they would not speak to you for weeks. This is called taanton.
Book Name: Anger (Page #7 Last line & Page #8 Paragraph #1 & #2)