When someone is communicating with you - in speech or in writing - pay attention to words that are loosely defined. The words that we assume we know what they mean but could be mistaken.
For example, someone might say:
"I think it's great that they were able to get the funding"
We could probably deduce the meaning. The problem is we are filling a lot of gaps for the person speaking / writing. For example when they say it's "great" how great do they mean? Is this greatness an opinion ("think") or a fact? We might make assumptions and get things wrong.
Where does the lasso come in?
Watch out for words that are open to interpretation. Notice when you feel you have to 'fill in the blanks". The lasso represents your attention ready to catch vague words as they are passed before you. Grab a word or two, even thought it interrupts the flow of information. Check what they really mean before letting them continue.
So when someone says:
"I don't think he knew all the details"
we could ask:
"Who is he?" or
"What makes you think he didn't know" or
"What were the details?" or
"When you say details what do you mean?"
The point is not to let the assumptions get past you.
The minute you start to lasso vague communication your ability to challenge assumptions increases. You might also find you're not the only one that has made assumptions. Getting clarification helps everyone. You'll also show you're really listening.
It's much easier to solve a problem when we understand what the issues really are. Not bad for a little bit of verbal lassoing!