Idea: train the skill "ask for examples" instead, which seems easier to train, and bootstraps you into being more specific. I am not usually confused about my own thoughts, but I am often confused when others are trying to explain their ideas.

Example: explaining a startup idea to my friend today, I said "...and the viral strategy for this payments app could be loaning money to people". He was confused and asked for an example, so I said "let's say we are at a coffee shop. I have no cash, you have the payment app, and I want to borrow money for coffee. You tell me to download the app, so you can loan me the money. Then I can get my coffee, but to pay you back, I have to complete the signup process." -- here, I was incorrectly assuming my friend had all the same context I did with respect to viral strategies.

Exercise: after explaining the virtues of asking for examples, start to move onto another topic. A confederate in the audience yells "can you give an example?" Everyone giggles, the instructor says "I'm glad you asked!" and the exercise is explained: Students pair off and start telling stories to each other, intentionally leaving out details. The other person's job is to try to figure out where the details are being elided and say "example?" at the right time.

For the rest of the session, the instructor intentionally leaves out details, awarding points for the first student who notices missing details and asks for example.

Intentionally set the atmosphere of jumping in / cutting in on an explanation, since it is much more valuable right then as opposed to later.