(Urgent) In which episode did Gintama Nakagintoki first become a teacher?

Often, he will wear a white coat and talk about some boring questions, such as why he always wears the same clothes and so on~ I will help you find it~~ Chapter 5 "To make friends, you need to make friends." People who can still call each other nicknames even when they become old people" (Training 5) + A brief introduction to the characters of Group 1 in 3 years, Chapter 8 "There is only a thin line between perseverance and stubbornness" (Training 8) + 3 Year Z Group 2 Disappearance of Dizi Chapter 11 "The rotten meatballs are not meatballs at all, you idiot" (Lesson 11) + Please give me some advice! Ginpachi-sensei 2 The so-called word for sugar Chapter 19 "Why is the sea so salty? It's not because you city dwellers urinate while swimming!!" (Lesson 32) + Please tell me! Ginpachi-sensei 3 Gin's clothes Chapter 33 "It's rude to get someone's name wrong" (Lesson 54) + Please give me some advice! Ginpachi-sensei 4 When will he be considered an uncle? Chapter 40 "Having a child must have a plan" (Lessons 57~58) + Year 3 Z Group 3 What is the difference between aliens and celestial beings? Chapter 46 "Wait until you are 20 before you go to a hotel" (Lesson 74) + Please give me some advice! Ginpachi-sensei 5 Master House Three-person Drawing Method Chapter 73 "Are Matsutake Really So Delicious? Think Again" (Lesson 41) + Mr. Ginpachi's Escape Preview Chapter 107 "It's Hard for Children to Understand Parents' Hearts" ( Training 184~186) + Mr. Ginpachi of Group Z in 3 years 6 The problem with the number of people in the true selection group is all here~~