I agree that this dream happened because of the death of your mother. I have noticed that all white dress in a beautiful setting nearly always denotes that. You are the master. You are saying to yourself that living life and achieving things sometimes hurts, and that master acknowledge that pain, and keep going. I would suspect that you clothe your hurts, which is why the master was nude. IMO, the large penis is not sexual, but an acknowledgment by your mother or your recognition that even though your mother didn't show it, that she knew you were quite a person, that she respected you even though she really didn't show it.
So, know that your mother respected you and that you can show your hurts. It doesn't mean by showing a hurt, you're a loser, or you will lose it. You're a master who can achieve and still show feelings.