It means nothing, it is a verbal form impossible. Let's see, the word Afayaivo means nothing in Asturian. Correct divisions would be Bienveniu. The confusion I think it comes because when you receive several people in a house you can tell them Afayaivos, i.e., would like to say, I find good, as in your own home. It comes from the verb afayar. It is said that Bienveniu would say Spanish Bienvenido. While saying Afayate would say encuentrate at home.
