In a poem where the speaker admits that he "never [gets] laid," (31) it's not surprising to learn that there's not a whole lot of sex happening in "America." The speaker's focus instead remains largely political throughout the poem. Even when there is mention of sex in this poem, it's usually to support a political observation.
We learn that the speaker's "national resources consist of […] millions of genitals" (50), and that he creates "strophes" of "all different sexes" (55). Really, though, that's not as much about sex per se as it is about recognizing that sexuality is a component of both art and a country's citizenry. In the poem's last line, we learn that the speaker is "putting [his] queer shoulder to the wheel," (80), but again, sex is used in a political way—to show that this outsider is going to set things right! But, not have sex. Not in this poem, anyway.