VAWMA = VWMA and WMA combined. Simply put, this attempts to determine the average price per share over time, weighted heavier for recent values. Uses triangular algorithm to taper off values in the past (same as WMA does).
Why use this? Let's say the earliest bar of the VWMA has a huge amount of volume. That means that when the next bar arrives, there will be an abrupt change in the moving average that doesn't represent the current value properly. VAWMA eliminates this problem by triangular weighting each bar.