Transcendental devotional service has five stages of reciprocation:
1. The self-realization stage just after liberation from material bondage is called the Sänta, or neutral stage.
2. After that, when there is development of transcendental knowledge of the Lord’s internal opulences, the devotee engages himself in the däsya stage.
3. By further development of the däsya stage, a respectful fraternity with the Lord develops, and above that a feeling of friendship on equal terms becomes manifest. Both these stages are called säkhya stage, or devotional service in friendship.
4. Above this is the stage of paternal affection toward the Lord, and this is called the vätsalya stage.
5. And above this is the stage of conjugal love, and this stage is called the highest stage of love of God, although there is no difference in quality in any of the above stages. The last stage of conjugal love of God is called the mädhurya stage.
As explained by Sri Ramakrishna
"Śānta, the serene attitude. The rishis of olden times had this attitude toward God. They did not desire any worldly enjoyment. It is like the single-minded devotion of a wife to her husband. She knows that her husband is the embodiment of beauty and love, a veritable Madan.
"Dāsya, the attitude of a servant toward his master. Hanuman had this attitude toward Rama. He felt the strength of a lion when he worked for Rama. A wife feels this mood also. She serves her husband with all her heart and soul. A mother also has a little of this attitude, as Yaśoda had toward Krishna.
"Sakhya, the attitude of friendship. Friends say to one another, 'Come here and sit near me.' Sridāmā and other friends sometimes fed Krishna with fruit, part of which they had already eaten, and sometimes climbed on His shoulders.
"Vātsalya, the attitude of a mother toward her child. This was Yaśoda's attitude toward Krishna. The wife, too, has a little of this. She feeds her husband with her very life-blood, as it were. The mother feels happy only when the child has eaten to his heart's content. Yaśoda would roam about with butter in her hand, in order to feed Krishna.
"Madhur, the attitude of a woman toward her paramour. Radha had this attitude toward Krishna. The wife also feels it for her husband. This attitude includes all the other four."