CC Ādi 5.139

kvacit krīḍā-pariśrāntaṁ
gopotsaṅgopabarhaṇam
svayaṁ viśrāmayaty āryaṁ
pāda-saṁvāhanādibhiḥ
Synonyms: 
kvacit — sometimes; krīḍā — playing; pariśrāntam — very much fatigued; gopa-utsaṅga — the lap of a cowherd boy; upabarhaṇam — whose pillow; svayam — personally Lord Kṛṣṇa; viśrāmayati — causing to rest; āryam — His elder brother; pāda-saṁvāhana-ādibhiḥ — by massaging His feet, etc.
Translation: 
“Sometimes when Lord Kṛṣṇa’s elder brother, Lord Balarāma, felt tired after playing and lay His head on the lap of a cowherd boy, Lord Kṛṣṇa Himself served Him by massaging His feet.”