'Explain this' look for the skills of dealing with the unexpected situations we face every day in the life, a reframe the situation you face.
The first step is to ask the participants to build a model of whatever subject they like, anything that comes to their mind to build up.
You can have five nouns pre-defined in advance, or you can ask to write these nouns.
A noun can be anything, chicken factory, haunting crocodile machine, the wedding, the new year party.
What people are expecting is you ask them to explain the model they have built. But you don’t; you ask them to pick and chose one noun and explain their model. For example, if they chose “chicken factory”, describe their model as this kind of factory.
Storytelling comes in place, and you will see who has the imagination to elaborate a coherent story. Some people may not have the skill to embellish the story, and they get blocked; however, invariably, they say something, even a short phrase.