Tactful person usually tries to warn create awkwardness of the situation, but to avoid them altogether unlikely anyone will. If foresee the situation, we can translate all what is happening in jest, or to represent all in a slightly different light.
In conflict situations, to the extent possible, to avoid a dispute. In most cases, the correct solution would be to give in, not exacerbating the conflict, and apologize. Because of this, You most likely will not only lose, but will exalt himself in the eyes of others.
If to give the dispute is impossible, try to convince people politely and tactfully. In an embarrassing situation, do not raise your voice, stick friendly tone. Say, looking in the eyes, carefully listen to his arguments.