The previous explanation was taken directly from another website.
A Daddy-Dom is simply the Dominant partner in a D/s relationship. Like a Master or Dom, a Daddy is the top in their relationship and owns or cares for the submissive. Depending on your own personal preferences and relationship dynamic, a Daddy can be many things to his little but there are some generalities that exist in most Daddy/little relationships.
Unlike age players or role players, Daddies do not consider themselves a father to their little. They consider their role much like how a Dom would look at their role over their sub. Though their little may call them Daddy, they are not observed as a father and they don’t look at their little as if they were their child.
Daddies are in charge of their little. While they do not pretend to be their little’s father, they will take on a parental role as the Dominant. They are there to protect, guide, nurture and love their little. While in some D/s relationships, the Dominate may order their submissive frivolously for their own pleasure, a Daddy will order or set rules for their little based on nurturing goals and what is best for their little.
This can be asked the same for any relationship. Daddies like little's based on their own personal likes and dislikes and what they find attractive. A Daddy should enjoy the regression that their little naturally does and appreciate the child-like attributes of their little, but they will also find their adult side attractive.
There is a big difference between Daddy as a title for a Dominant in a D/s relationship and Daddy as a title for a father. While many have some reservations about this title, it is nothing more than that: a title. Daddies are not interested in pedophilia, incest or any other paraphernalia associated with children even though their title is often misunderstood and associated with that. When a little calls her Daddy by title, the feeling associated is nothing like the feeling she would get when she calls her father the same title. It’s the same with any other multi-use word in our language. For instance, the world love can be used to describe many things. You don’t have the same feelings for when you say you love bubbles as you do when you say you love your spouse.
A lot of people just starting out in this lifestyle wonder if it’s still okay to have sex. As two consenting partners in a loving relationship, sex should be normal. Just like any other relationship, sex is natural and healthy for growth and bonding. Sex in a Daddy/little relationship is not done like that of role players where the sexual attraction may in some cases stem from deep seeded interest in incest or pedophilia. Sex between a Daddy and his little is just like sex between any people in a relationship; as two consenting adults.
Daddies are very similar to Masters but there are some striking differences. First, Daddies cherish their submissive's little side and encourage her to come out and play. Second, Daddies are strict about different things. Where a Master may be strict about procedure and protocol, Daddies are more concerned with their submissive's goals and needs. Third, a Daddy can be more playful than most Masters. Masters tend to have to be more rigid with their submissive or slaves. Of course, we aren’t saying Masters are unable to show affection or be playful. But as a Daddy, playfulness is practically a part of the job description. It’s something you would have to do in order to keep up with your little.