who lodged his horn and staff in the crook of his arm
'With horn and stick tucked between elbow and side' — the standard way the cowherd boys carry their horn and herding-stick; Kṛṣṇa adopts every detail of cowherd practice.
भुजसन्ध्यन्तरन्यस्तशृङ्गवेत्रः शुचिस्मितः ।वामपाणिस्थदध्यन्नकबलः कलभाषणः॥
bhujasandhyantaranyastaśṛṅgavetraḥ śucismitaḥ ·vāmapāṇisthadadhyannakabalaḥ kalabhāṣaṇaḥ
who lodged his horn and staff in the crook of his arm
'With horn and stick tucked between elbow and side' — the standard way the cowherd boys carry their horn and herding-stick; Kṛṣṇa adopts every detail of cowherd practice.
of bright, pure smile
'Of pure smile' — Kṛṣṇa's smile while eating with his friends is described as 'pure' (śuci) — undimmed by any self-consciousness, a child's open smile.
holding a ball of curd-rice in his left hand
'With a ball of curd-rice in his left hand' — Kṛṣṇa eats curd-rice in the cowherd manner, taking small portions in the left hand and putting them in his mouth with the right.
of sweet, soft speech
'Of sweet, slightly indistinct speech' — Kṛṣṇa's voice while eating and talking with his friends is described as kala-bhāṣaṇa — the slightly-blurred, sweet speech of childhood.