The speaker feels overwhelmed by something too big to hold. "Infinity makes my head full" suggests a mind stretched past its limits, as if endlessness has been poured into it. The title, which in Latin means "Sea of Desire," sets up the central image: a sea that is both a place and a craving.
In the poem, the speaker claims to have been "king of the sea," a proud, almost intoxicated sense of ownership. But the kingdom is built on drinking. "We drank and drank / till water was / the wish of all" turns thirst into a shared obsession, where wanting becomes the only thing left. The final line plays on a double meaning. To be "in the drink" can mean being in the water, but it also hints at being drunk, or lost in something. The mood is dreamy and dizzy, mixing grandeur with a hint of helplessness. The speaker seems to have never quite come back from that overflowing, endless wanting.