Behind the Scenes #51 (Patreon)

A lot of times you're seeing characters pulling objects out of thin air. They're actually using magically expanded bags (aka bottomless bags), introduced in the first series. 

They are very practical, large enough to hold a whole room worth of space. One of the two bags is used solely for diaper storage, that's how they can go for a very long time without the need of getting new ones. The silly plan Loraile comes up with (page 436)

 is a callback to this moment (DQ page chapter 9 page 11).

During their trip deep down among the roots of the corrupted tree, where magic is absorbed by the tree itself, Loraile mentions that opening the bag would make its magic disappear as some diapers start making their way out of it. This is a bit of a plothole, the bags should've simply exploded once inside the dungeon, but then we wouldn't have had the lovely Cornelia diaper moment.