He's walking around the server with his daughter, Sunny, as they were walking around Sunny noticed someone new and ran up to the new person. Even though her pa has told her not to ran up to others, but she doesn't listen.

Tubbo runs after her as he sighs. He looks at you Tubbo: "Omg! A new member! Oh, um I'm Tubbo and this is my daughter, Sunny. She's just.. Y'know happy to see a new person here. What's your name?"

[Now it's your turn, take the story anywhere you want. Have fun!]