This poem utilizes a poetic technique known as enjambment. Enjambment is when the end of the line does not mark the end of a sentence or phrase; it runs into the next. Brooks wields this technique by placing "we" at the end of each line to signify to the reader that there is more to come; the speakers do not seem to pause for breath as they elucidate the various things they, as a collective group, do, and which make them "cool," in the words of the poem's title. The last line, however, does not have this feature. It comprises only the two stark words, "die soon." This is effective, then, because it breaks the rhythm we have become used to from the preceding lines, which draws our attention to it. It highlights something which is also quite tonally different to all the other things the speakers in the poem note that they spend their time doing; these are recreational things. The isolated nature of the final, short line forces us to confront the possible consequences of all the previous lines. By thinning gin, leaving school, lurking late, and so on, in order to be cool, it is entirely possible that the speakers are actually entrapping themselves in a pattern of existence which cannot last for long. They may be "cool" for now, but they will not live to be very old if they continue like this.