अत्स्यन्नं पश्यसि प्रियमत्त्यन्नं पश्यति प्रियं भवत्यस्य ब्रह्मवर्चसं कुले य एतमेवमात्मानं वैश्वानरमुपास्ते बस्तिस्त्वेष आत्मन इति होवाच बस्तिस्ते व्यभेत्स्यद्यन्मां नागमिष्य इति ॥ ५.१६.२ ॥
In plain words
Thou eatest food and seest what is dear; and he eats food and sees what is dear, and the lustre of Brahman appears in his family, who worships this Self, Vaiśvānara, thus. But this is only the bladder of the Self," he said. "Thy bladder would have burst, hadst thou not come to me."
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
बस्तिस्त्वेष आत्मनो वैश्वानरस्य, बस्तिः मूत्रसंग्रहस्थानम्, बस्तिस्ते व्यभेत्स्यत् भिन्नोऽभविष्यत् यन्मां नागमिष्य इति ॥
In plain words
This is indeed the bladder of the self Vvaiśvānara, the bladder being the receptacle for urine; your bladder would have burst and split apart if you had not come to me.
Close to the Sanskrit
This indeed is the bladder of the self Vvaiśvānara, the bladder is the place for gathering urine; your bladder would have burst, it would have been split, if you had not come to me.