Primarily we need to understand our eternal relationship with Krishna, the about the the above mentioned relationships.
Constitutionally we are a part & parcel of Krishna in a loving servant relationship. nityo-niyanam chetanas-chetananam eko yo vidhadhat kaman...Here servant does not mean the slavery which is found in this material world. The kind of servitorship found there in the spiritual world, Goloka Vrindavana is transcendental to these material inebrities.
The exchanges between these part n parcels and the Supreme Lord happens primarily in below mentioned five kinds. Since now we are impure, conditioned in the material world, we should always serve in the Lord in dasya rasa ( relationship with the Lord in a servant mood). Actually, Krishna doesn't need our service. But for our purification, we serve him. Also, the other mentioned rasas(mellows) occur once we attain the stage of pure love for Godhead, Krsna. This is the process recommended by Acharyas of proper Sampradayas/ schools of thought like Gaudiya Vaishnavas, Sri Sampradaya, Madhva Sampradaya and Rudra Sampradaya. It is not a whimsical process.
These rasas are eternally manifested in the hearts of the pure devotees.
1. Santa (neutrality)
Activities: Meditation and worship of Brahman and Paramatma, Appreciating Krishna's beauty
Qualities: Full attachment to Krishna
Examples: Sukadeva Goswami , Bilvamangala, Four Kumaras, Navayogendras
2. Dasya (servitude)
Activities: Menial service , Prayers,Obeisances,Fanning
Carrying umbrella,Supplying betel,Cleaning clothes
Qualities: Full attachment to Krishna's service
Examples: Brahma, Daruka,Uddhava,Pradyumna,Bhisma
3. Sakhya (Friendship)
Relaying confidential messages,Singing,Dancing
Qualities: Full attachment to Krishna Service Relaxed intimacy
Examples: Sudama,Arjuna,Bhima,Ujjvala,Stoka Krishna
4. Vatsalya (Parental)
Qualities: Full attachment to Krishna's service,Relaxed intimacy,Maintenance
Examples: Yasoda-mata,Nanda Maharaj,Devaki,Vasudeva
5. Madhurya (Conjugal)
Activities: Exchange of glances and sweet smiles, Dancing
Kissing,Embracing,Talks and arguments
Qualities:Full attachment to Krishna's service,Relaxed intimacy,Maintenance,Offering the body,
Examples: Srimati Radharani, Rukmini, Satyabhama,Lalita,Visakha,Candravali
If we can observe, all of the above mentioned rasas contain Full attachment to Krishna service. All other rasas occur higher stages of Devotional service to the Supreme Lord Hari. We should not at all try to imitate these kind of relationships with the Lord in our present stage. Those who imitate these kind of relationships are called sahajiyas and r not accepted by any authorise sampradaya of Vedic Science.
Teachings of His Divine Grace A.C.Bhaktivedanta Swami Srila Prabhupada,