Subtle?
If one guy telling the other that he's a 'slow learner' is subtle, what constitutes flagrant in your book?
There must be procedures in place to deal with this sort of abuse. Maybe it's just me but I had to put up with enough nonsense when I was in the right seat that I find myself oddly reluctant to put up with any coming from the right seat. Aside from possibly getting some time off the amount later spent in Purgatory, if your beliefs run that way, why bother putting up with this sort of thing at all? Isn't life just too short?
That Air Florida crash in Washington cited the FO's self-publicity, giving an inflated version of his previous Air Farce career, as one factor in the accident, so that good CRM might mean being able to speak up against this sort of 'putting down' without coming across as terminally rude or unreasonable.
I usually just have to point to the basic unfairness of life as the root cause of some Lone Eagle being forced to fly under the command of such people as me. That is about the only comfort I can give, while also pointing out that we can always go see the Chief Pilot if this situation is just insurmountable. So far this approach seems to have kept our little craft shiny side up.