Somehow I knew this day would come; just not this soon

Riley has discovered his penis, in what will (in all probability) become a lifetime love affair (to paraphrase a comedian who's name I can no longer recall). He sits in the bath and twiddles it between his fingers like banjo strings and I can't help but cringe a little and I don't even have one! What do I do? Turn my head and ignore it or tell him to stop it? I'm not overly concerned, don't get me wrong. I'm just getting used to boy-stuff!