When the Serenitea Pot was first implemented in version 1.5 of Genshin Impact, only the players themselves can enter the Realm Within, leaving poor Paimon to wait outside until you come back out. With the version 2.3 update, you now have the option to bring Paimon and have her live inside the pot, too!
How to summon Paimon in the Serenitea Pot?
First, make sure that you have updated the game to version 2.3.
Next, enter the Serenitea Pot by interacting with it through your inventory or by using a teleport waypoint to teleport to a sub-space waypoint placed inside your pot.
Finally, access the Placement menu, go to the Companion tab, and select the Paimon icon to see Paimon as an available companion. Select her and place her wherever it is possible or wherever you want her to be within your realm. And that’s it! You’ve just invited Paimon into your realm! Don’t forget to save any changes done within the Placement tab.