In the Bhakti-rasāmṛta-sindhu (3.2.93), these divisions are described:

ayoga-yogāvetasya prabhedau kathitāv ubhau

“In the mellows of bhakti-yoga, there are two stages — ayoga and yoga.” Ayoga (viyoga) is described in the Bhakti-rasāmṛta-sindhu (3.2.94) as follows:

saṅgābhāvo harer dhīrair ayoga iti kathyate
ayoge tvan-manaskatvaṁ tad-guṇādy-anusandhayaḥ
tat-prāpty-upāya-cintādyāḥ sarveṣāṁ kathitāḥ kriyāḥ

“Learned scholars in the science of bhakti-yoga say that when there is an absence of association with the Supreme Personality of Godhead, separation takes place. In the stage of ayoga (separation), the mind is filled with Kṛṣṇa consciousness and is fully absorbed in thoughts of Kṛṣṇa. In that stage, the devotee searches out the transcendental qualities of the Supreme Personality of Godhead. It is said that in that stage of separation, all the devotees in the different mellows are always active in thinking of ways to attain Kṛṣṇa’s association.”

The word yoga (“connection”) is thus described in the Bhakti-rasāmṛta-sindhu (3.2.129):

kṛṣṇena saṅgamo yas tu sa yoga iti kīrtyate

“When one meets Kṛṣṇa directly, that is called yoga.”

In the transcendental mellows of neutrality and servitorship, there are similar divisions of yoga and viyoga, but they are not variegated. The divisions of yoga and viyoga are always existing in the five mellows. However, in the transcendental mellows of friendship and parental affection, there are many varieties of yoga and viyoga. The varieties of yoga are thus described:

yogo ’pi kathitaḥ siddhis tuṣṭiḥ sthitir iti tridhā

“Yoga (connection) is of three types — success, satisfaction and permanence.” (B.r.s. 3.2.129) The divisions of ayoga (separation) are described as follows:

utkaṇṭhitaṁ viyogaś cety ayogo ’pi dvidhocyate

“Thus ayoga has two divisions — longing and separation.” (B.r.s. 3.2.95)