The title of "Having a Coke with You" flows right into its opening lines, so that, syntactically, they're part of the same sentence. (English-language poets had started to play with this titling effect a generation before O'Hara; one famous example is Marianne Moore's "The Fish.") Thus, "Having a Coke with You" is the subject of a sentence whose very long predicate begins: "is even more fun than going to San Sebastian, Irún, Hendaye, Biarritz, Bayonne / or being sick to my stomach on the Travesera de Gracia in Barcelona."
These proper nouns refer to places in Spain (San Sebastian, Irún, Travesera de Gracia in Barcelona) and France (Hendaye, Biarritz, Bayonne). Most are ritzy coastal resort towns, with the exception of Barcelona, a large coastal city in Spain's Catalonia region. The Travesera de Gracia (also spelled Travessera de Gràcia) is a street running through the Gràcia district of Barcelona.
- All of these places are tourist destinations that O'Hara himself had visited. In fact, shortly before writing the poem, Frank O'Hara had been on a work trip to Spain. Like many of O'Hara's poems, then, this one is autobiographical.
- The "You" refers to his actual lover at the time, the dancer Vincent Warren (though the poem never mentions him by name, in part due to O'Hara's desire to keep his sexuality ambiguous in the homophobic culture of mid-20th-century America).
In this opening simile, O'Hara declares that the simple act of "Having a Coke with You" is better than visiting all these fancy French and Spanish towns. Later lines make clear that the two lovers are enjoying this Coke while walking around New York City (where both men lived at the time).
Coke is a cheap and classic American product, sometimes used as a symbol of America itself, so this American speaker is suggesting that the simplest possible experience with his lover—drinking an ordinary soda on an ordinary day—"is even more fun" than visiting exotic tourist spots. (The comparison to "being sick to my stomach [...] in Barcelona" sounds counterintuitive—stomachaches usually aren't pleasant!—but O'Hara's implying that he got sick there from overindulging in alcohol, i.e., having too much fun.) These days, O'Hara doesn't need fine wine or a fancy destination; staying close to home and sharing "a Coke with You" is romantic enough.