Being refused by pipes isn’t new to Mario, but in Paper Mario: The Thousand-Year Door, they can be a little forward about it in one chapter. Starting Chapter 4 requires that you have your name written on your butt just to get to Twilight Town, but there’s another pipe within that behaves the same way with no explanation.
The pipe is located in a house within Twilight Town beside the item shop. You’ll know the house because the pipe is a dominant feature of its single room. If you attempt to go down the pipe, you’re told, “The pipe rejected you.”
Don’t worry about it. Don’t pay any attention to the pipe. It’s not important right now. It isn’t a puzzle that is keeping you from reaching vast loot. Don’t waste your time or energy on it. You’ll discover its use in due course.
The pipe actually connects to an area in Creepy Steeple. During the chapter, you’ll descend to the basement in search of the name of the person who stole Mario’s name and body. Once you finish that part, there’s a pipe that will take you back to Twilight Town. The reason it rejects you is because it’s a one-way trip. A temporary reprieve from traipsing back and forth between Creepy Steeple and Twilight Town.
There’s nothing you can dow ith it before that, and there’s nothing you can do to have it accept you. Instead, you’re going to have to accept it as it is. Every pipe is beautiful, flaws and all.
