For my discussion of a poets' usage of heroic couplets I have selected the penis poem. Rochesters' The Imperfect Enjoyment's utilization of these heroic couplets is as artful as its brutalization of an uncompromising body part is tactless. (You see what I did there?)
There is an obvious shift in tone beginning with line 25 "But I, most forlorn, lost man alive..." This shift comes after 24 lines of a beautifully described scene of passion. The heroic couplet verse form is employed two different ways both before and after this shift. The first 8 lines have a halting feeling with a pause in the center of each line to truly emphasize each iamb. Line 6 is a good example of this "She clips me to her breast, and sucks me to her face." Passion is evident in the line but there is no urgency yet. But the enjambement between lines 8-9 steps up the urgency of the passion and begins to build to the sudden change in tone. "Swift orders that I should prepare to throw/The all dissolving thunderbolt below." Excitement comes from both the words and the shift in how they are read. From halting to sudden and almost impatient. The urgency builds until line 24 where Rochester is asked "must we not pay a debt to pleasure too?" Lines 25-45 quickly and summarily describe his predicament and the irony at his little buddy's past willingness that is nowhere to be found now. We are given 2 sets of "triplets" which emphasize even further the desperation of his introspection. Line 46 begins the shift from desperation to anger in which he lambastes his penis frantically and furiously. Gone are the desperation of triplets and the halting iambic buildup. What we have here in these final lines are twin daggers of pure penis putdown gold. The heroic couplets are less heroic and much more demonically vile. My favorites? "What oyster-cinder-beggar-whore didst thou e'er fail in thy life before?" and an image of a hog that doesnt bear repeating. The poem ends with an indention and a brilliant summary of Rochester's point.
So why the heroic couplet rather than anything else? It seems to be far more adaptable to Rochester's purposes and accomplishes a buildup effect. The passionate foreplay scene's halting beginning and sudden shift is accomplished with rhymed lines in iambic pentameter with a slightly increasing rhythm. The second portion of the poem exudes a desperation due to the inclusion of triplets and the quickly read and executed rhymes. The final glorious crescendo that are the final 30ish lines of this poem have a different sort of scheme concerning the couplet. They're practially a series of "two liners" in which the first line of a rhyme is more or less a setup and the second one a punchline. Rochester utilizes heroic couplets to give vivid life to a humorous situation and make it far more funny.