Not every item in a podcast feed has the same purpose. A regular episode, an extra conversation and a short introduction to the show may need different episode-type labels. Choose the label for the item's role rather than as a way to make it seem more important.
Describe the content honestly
A full episode contains a normal installment of the show. A bonus item adds material outside the usual sequence. A trailer introduces or promotes the show or season. Check the current publishing destination's explanation of these values, since presentation can differ between listening apps.
Write a title and summary that still make sense if the app does not emphasize the type. For example, a trailer summary can explain what the series covers and when listeners should start, without pretending the short introduction is a complete interview.
Keep episode numbering separate from type. A bonus item does not need to borrow a regular episode's identity simply to appear near it.
Preview the actual feed item
Before release, review the type, title, publication date and enclosure together. A correct label with the wrong audio file is still a publishing error. Open the listening copy and confirm that it matches the summary.
If you change the type of an existing item, preserve its stable identity unless you are intentionally publishing a new episode. Record the reason for the update so another team member does not reverse it later.
The useful result is a feed where listeners can understand what each item offers. A consistent editorial choice matters more than trying to force the same visual order in every possible listening application.