I have a really close acquaintance, Emily, who knows me very well.* We often have constructive debates about life things. During them, she always wants to help me, and we argue calmly and intelligently, without any raised tone.
Partly because of how well she knows me, Emily has the bad habit of getting into long, 5-minutes monologues, explaining bit-by-bit what she thinks I/we should do, what she thinks is the problem with my attitude, etc. This happens when she really believes in what she's saying, and believes it's important. The problem is, there are usually a number of key points, or even the premise, that I disagree with, so after a time the monologue feels to take an irrelevant way, and I hardly get the chance to argue.
She doesn't leave any gap for a response, and I can't cut her word: when I do, the immediate response is "Please listen 'til I finish". Sometimes she does stop, but you clearly feel her frustration, feeling as she just couldn't explain everything - but if she did so, I wouldn't disagree. So even if we continue, she takes every opportunity to continue.
My aim is to cut those long monologues early, and get the chance to argue, without making Emily feel frustrated by me holding in her further arguments, and at least shepherd the monologue in a way I find more relevant. Can I do this, and how?
.* "Emily" is my mother (and I'm a grown-up). Though this explains the nature of our debates, I believe a general question is better for the site.