> “Oh, here’s the trick I just used in the debugger.”
Don't ever talk to one another during debugging sessions. Pick up your bug ticket, fix it, close the ticket. Everyone else has their own work to do so they are not interested in watching you pilot your heavily-customized IDE setup, and the boss doesn't make them.
> “I’ll sketch the architecture change I’m proposing on the whiteboard.”
Don't have whiteboard meetings about architecture. If you must, definitely don't invite juniors. In fact, nobody actually writing code to implement the change will be in the meeting at all. We are architects and managers, they are merely developers. They'll write what we tell them to write. In many organizations, even the people called "architects" are left out of these meetings, and probably even line managers. These are Director Level Decisions, after all.
> “Why don’t you shadow me in this meeting or interview or presentation?”
Easiest of the three. Just never ever have anybody "shadow" anyone for any reason. They have their own work to be doing.
I'm not saying these behaviors are good, but they are pretty much the default behavior in corporate jobs AFAICT.