SB 11.11.11

evaṁ viraktaḥ śayana
 āsanāṭana-majjane
darśana-sparśana-ghrāṇa-
 bhojana-śravaṇādiṣu
na tathā badhyate vidvān
 tatra tatrādayan guṇān
Synonyms: 
evam — thus; viraktaḥ — detached from material enjoyment; śayane — in lying or sleeping; āsana — in sitting; aṭana — walking; majjane — or in bathing; darśana — in seeing; sparśana — touching; ghrāṇa — smelling; bhojana — eating; śravaṇa — hearing; ādiṣu — and so on; na — not; tathā — in that way; badhyate — is bound; vidvān — an intelligent person; tatra tatra — wherever he goes; ādayan — causing to experience; guṇān — the senses, born of the modes of nature.
Translation: 
An enlightened person fixed in detachment engages his body in lying down, sitting, walking, bathing, seeing, touching, smelling, eating, hearing and so on, but is never entangled by such activities. Indeed, remaining as a witness to all bodily functions, he merely engages his bodily senses with their objects and does not become entangled like an unintelligent person.
Purport: 

In the previous chapter, Uddhava asked Lord Kṛṣṇa why an enlightened person, just like a conditioned soul, engages in external bodily functions. Here is the Lord’s answer. While engaged in bodily functions, an unintelligent person is attached to both the means and end of material life and therefore experiences intense lamentation and jubilation on the material platform. A self-realized soul, however, studies the inevitable defeat and suffering of ordinary persons and does not make the mistake of trying to enjoy the bodily functions even slightly. He instead remains a detached witness, merely engaging his senses in the normal functions of bodily maintenance. As indicated here by the word ādayan, he engages something other than his actual self in material experience.