How do you handle price matching of buyers?

[Jason Mak]

When you have multiple buyers, how do you handle a buyer who matches the highest buyer's price (or beats it by a little bit)?  

For example: buyer A offers $90k, buyer B offers $100k.  Buyer A immediately offers $102k.  

Do you ask for a best and final from both?  Or give buyer B a chance to match/beat? 

Just wondering how others play this game