Magistrate The why do you turn aside and hold your cloak

So far out from your body? Is your groin swollen

The humor in this passage pertains to the fact that the Herald has an erection. The reason he has an erection, of course, is because Lysistrata's plan is working and the women in Sparta have not had sex with the men. This produces the hilarious effect of the men walking around with huge erections that they cannot appease without the consent of their women. There are other specific facets of this passage that make a mockery of war as well. For instance, the Magistrate assumes the herald's erection is a lance -- which is a clever way of Aristophanes using war as a metaphor for sex. The implications of this passage, of course, is that without sex there is very little important in the world -- especially war and its travesties.

The phallic symbol represented by the soldier's erection and its likeness to a lance is highly prevalent throughout this play; much of the humor relates to phallic imagery. This fact is evinced again later on in the discourse between the magistrate and the herald. It is clear that the herald has come to arrange the terms of peace. He expresses this knowledge to the magistrate as the latter enquires how the Spartans are faring without having sex. The herald's response encompasses typical phallic imagery as a point of humor. He tells the magistrate: "We are broken, and bent double / Limp like men carrying lanthorns in great winds / About the city" (Aristophanes). The pivotal point of comedy in this passage is that the herald claims that he and the rest of the Spartans are...

The fact is that the Spartans are actually in no condition to have sex due to the manipulations of Lysistrata and of Lampito. The author, then, is attempting to create humor utilizing a metaphor which is related to the theme of this work of literature -- which is unequivocally sex (or the lack thereof). This passage indicates that the moral of the Spartans is as low or as deflated as a non-erect penis since they are not able to have sex. By terming the spirit of the Spartans as "limp" and "bent," Aristophanes is utilizing phallic imagery and symbolism to show how devastating Lysistrata's plan is to these soldiers. The humor is found in the fact that the author is utilizing sexual imagery to describe the effects of chastity (the lack of sex) on these soldiers. Audiences would have instantly recognized the parallel between this imagery and the play's theme, which is quite humorous.
Overall, there are many points of laughter invoked in this drama by Aristophanes; nearly all of them are related to the fact that for the characters in this play, sex is much more important than the social and political effects of war. Ultimately, this play serves as a means of setting the priorities for the Greeks involved in it. At the top of those priorities is sex, which is evinced by the fact that by the decision of the women of the competing armies in the Peloponnesian War to refrain from having sex, they are able to make their soldiers walk around with huge erections and to feel as inflated as a penis when it is not erect. Moreover, the importance of this part of life is evinced in the fact that initially, none of the women want to take this vow of chastity that Lysistrata advocates. All of these facts are hilarious and extremely satirical, and allude to the folly of war and the assessment that sex is much more preferable to it.