I think it's fairly safe to assume that most people are aware of the term casual sex and what it entails or it's closely related cousin, friends with benefits.
However, the situationship is a relatively new term used to describe intimate relationships that are sexual and even romantic in nature. They tend to have almost all the elements of a fully committed relationship, but the main difference is that situation ships tend not to have an official label attached to them.
This is often because one or both people in the situationship doesn't want to label the arrangement, often because they don't feel comfortable doing so, or because they want the freedom of being able to see other people and not be tied down to one person.
Unfortunately what often does tend to happen in these arrangements is that one person does at some point end up wanting a fully committed relationship, but the other person is happy with the arrangement as it is. Yep, you guessed it, messy..
Similar to the last episode, this episode assumes prior knowledge of attachment theory so if you're not very familiar with it, here are some resources to help get you acquainted:
https://www.iamreddi.com/post/counterfeit-connection-how-to-recognise-that-you-re-actually-in-a-situationship
https://www.amazon.com.au/Attached-Science-Adult-Attachment-YouFind/dp/1585429139