.NET - dump statement lambda body to string

Given the following statement lambda example:

var fMyAction = new Action(() =>
 {
    x += 2;
    something = what + ever; 
 });

What are possible ways to get the body of that lambda and dump it to string? (Something that will ultimately allow to write an extension method for Action class of this kind: fMyAction.Dump() which will return "x += 2; something = what + ever;").

Thanks