In plain words
You lick up and devour all the worlds on every side with Your flaming mouths, filling the whole universe with radiance. Your fierce rays burn, Vishnu.
Word for word
You lick [them] again and again, devouring on every side all the worlds with blazing mouths, filling the whole universe with brilliance; Your fierce rays scorch, O Viṣṇu.
The commentators
Bhagavadgītābhāṣyam
त्वं पुनः —
लेलिह्यसे आस्वादयसि ग्रसमानः अन्तः प्रवेशयन् समन्तात् समन्ततः लोकान् समग्रान् समस्तान् वदनैः वक्त्रैः ज्वलद्भिः दीप्यमानैः तेजोभिः आपूर्य संव्याप्य जगत् समग्रं सह अग्रेण समस्तम् इत्येतत् । किञ्च, भासः दीप्तयः तव उग्राः क्रूराः प्रतपन्ति प्रतापं कुर्वन्ति हे विष्णो व्यापनशील ॥ ३० ॥
In plain words
And you, for your part —
You are licking — that is, you are tasting them. Devouring — that is, drawing them down inside you. On every side — from every direction. The worlds, entire — all of them, every last one. With mouths — with faces. Blazing — burning bright. Having filled the whole world with your radiances — having pervaded it; and 'whole' is sa-agra, with its very tip included, complete: that is what the word means. And more: your rays — your blazes — fierce — cruel — scorch, that is, they give off scorching heat, O Viṣṇu — you whose very nature is to pervade.
Close to the Sanskrit
And you, moreover —
lelihyase — you taste; grasamānaḥ (devouring) — causing to enter within; samantāt — from every side; the worlds, samagrān (entire) — all of them; vadanaiḥ (with mouths) — with faces; jvaladbhiḥ (blazing) — shining; having filled with your radiances — having pervaded; jagat samagram (the whole world) — 'with its tip', that is, complete: this is the sense. And further: bhāsaḥ (rays) — blazes; your ugrāḥ (fierce) — cruel; pratapanti — they produce scorching heat; O viṣṇo — O you whose nature is to pervade.