Disclaimer: I don't always act as calmly and cooly on the field as profess - I too have fallen victum to trying to one-up a player's comment with one of my own...... but what I try to do (and many times succeed) in the case you describe.......
First comment:
Walk away - no retort needed, BUT if I just can't control myself, I have used "that's enough" and then turned and walked away.
That means the "mouth" would not have been able to give the follow up comment with out following you, creating a situation where (if he continues with ejectable statements) he's simply gone... poof....
