[Double_A]

In a vaccuum, I think this is a losing play. I will usually give up fairly easily the first few times someone does this too me. I give them the benefit of the doubt that their donks usually mean a pair because they usually do. If it becomes a problem, then I will start to make a few loose calldowns to send a message to my opponent.

Another option of course, is to play it like you did. Let him know early that you will make loose call downs when he donks, and then start folding later in the session.