Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 8

Sanskrit:

केशप्रसाधनोन्मर्दस्‍नपनाभ्यञ्जनादिकम् ।गुरुस्त्रीभिर्युवतिभि: कारयेन्नात्मनो युवा ॥ ८ ॥

ITRANS:

keśa-prasādhanonmarda-snapanābhyañjanādikamguru-strībhir yuvatibhiḥkārayen nātmano yuvā

Translation:

If the wife of the spiritual master is young, a young brahmacārī should not allow her to care for his hair, massage his body with oil, or bathe him with affection like a mother.

Purport:

The relationship between the student or disciple and the wife of the spiritual master or teacher is like that between son and mother. A mother sometimes cares for her son by combing his hair, massaging his body with oil, or bathing him. Similarly, the wife of the teacher is also a mother (guru-patnī), and therefore she may also care for the disciple in a motherly way. If the wife of the teacher is a young woman, however, a young brahmacārī should not allow such a mother to touch him. This is strictly prohibited. There are seven kinds of mothers: These mothers are the original mother, the wife of the teacher or spiritual master, the wife of a brāhmaṇa, the king’s wife, the cow, the nurse and the earth. Unnecessary association with women, even with one’s mother, sister or daughter, is strictly prohibited. This is human civilization. A civilization that allows men to mix unrestrictedly with women is an animal civilization. In Kali-yuga, people are extremely liberal, but mixing with women and talking with them as equals actually constitutes an uncivilized way of life.