How do you explain the phone calls?

So, most of the things that Wilfred does can easily be explained as Ryan doing it and just not remembering, like sending people emails or whatever. But, how can this possibly explain him getting phone calls from Wilfred and other people recognizing that the phone is ringing? It's not like Ryan can be in two places at once calling himself. I can't remember all the instances of this, but the one I do remember is when he is meeting with his dad in S4E1. His phone rings and he sees it's Wilfred calling, and his dad asks if he needs to take it. I guess it's possible that he's just getting calls from someone else and his mind is seeing it as Wilfred.