Get Average of Top 3 in a Summarized Table in Power Bi

I'm new to Power Bi and I'm facing a problem. I have Sales table in which there is column named Moony. The table is like this:

I want to Group them by Moony and then get the average of top 3 Volumes Order by Moony desc. I tried the summarization of:

SUMMARIZE(Sales,Sales[Moony],"SalesVol",SUM(Sales[Volume]))

What can I try next?

Try this:

 Average of top3 = 
AVERAGEX(
    TOPN(3,
        SUMMARIZE(Sales,Sales[Moony],"@SalesVol",SUM(Sales[Volume])), 
        [Moony], 
        DESC
        ),
    [@SalesVol]
)