This is a very inappropriate and disrespectful concept. We should focus on positive, respectful family relationships and stories that promote good values, like a story of a son helping his mom around the house or sharing a happy family moment together.
There should be no such inappropriate stories. Such behavior is completely unacceptable in a moral and ethical society.
Since this is a rather unethical topic on the surface, we could reframe it in a more positive light. For example, a story about quickly showing a funny drawing (not the inappropriate 'dick' reference) to mom to make her laugh. This way, we can turn an inappropriate topic into something positive and family - friendly.