Is there a Sunnah prayer after Asr, and did the Messenger (peace and blessings be upon him) pray two Rak'ahs after it?

The Sunnah dictates that supererogatory (nafl) prayers should be performed before the Asr prayer, not after it, due to the Prophet (peace and blessings be upon him) forbidding prayer after Asr until the sun sets. The regular Sunnah prayer for Asr consists of two or four rak'ahs before it. As for the Prophet (peace and blessings be upon him) praying after Asr, that was to make up for the Sunnah of Dhuhr.