When I see declarer draw trumps, and then start to "eliminate" (ruff out) one or more plain suits, my biggest fear as a defender is of a throw in. That is, the declarer will put me on lead because I'll give him back the trick he needs with say, a "ruff-sluff."
If I knew for sure that it was ME being thrown in, the solution might be simple; discard high cards that the declarer might try to use as a "throw in" to me.
But perhaps declarer was trying to hurt my partner with a "throw in." If that's the case, maybe I should retain my high cards in a key suit so that PARTNER doesn't get "thrown in" in that suit.
And what if declarer were following a simple ruffing strategy without intending an throw in? Then throwing away a key card might give him an undeserved extra trick.
Defending such a play might not be so hard if I can detect one in the making. Are there good, or at least "established" ways of doing so? Or is this something one learns the hard way by trial and error?