This fleshbotted article is a damn interesting read.

I wonder what kind of sex prop is going on in the current war.

Both the Axis and the Allies printed aerial propaganda leaflets using sexual themes in an attempt to demoralize enemy soldiers at the front. Did these leaflets work? Did the finders become emotionally crippled and unable to carry on their duties and responsibilities? Just the opposite occurred. The “pin-up” pictures became collectors items sought after by the troops who greedily collected and swapped them. If anything, the leaflets raised morale. There is no doubt that they were the most heartily appreciated propaganda leaflets used in World War 2. We can probably state that they were the most widely read and circulated enemy documents of any war.

So, why were they used? Edward Donnerstein says in The Journal of Personality and Social Behavior (Vol. 39, 1980, p. 269-277) “When males have not been angered or have been exposed to mild erotica, aggressive behavior has been reduced.” He later says, “In summary, the present results suggest that highly arousing nonaggressive-erotic stimuli can be a mediator of aggressive behavior by males toward other males under certain condition.” Could it be that our enemies believed that the sexual leaflets would take the “fight” out of the American soldier?

I once interviewed the top British forger of the war. He was the man in charge of printing the black British leaflets. He said about the sex leaflets “They did nothing to the enemy, but they were popular among the “adolescents” working for me. They did not demoralize the enemy, but they were excellent for the morale of the British agents who handled and distributed them.” An American propagandist once told me that he did not like to disapprove these strange and exotic concepts because it tended to stifle the creativity of his artists. It seems that on the Allied side at least, sex leaflets were produced mostly because the bosses thought it was a good way for their people to stretch their imaginations and remain creative.

[…]

Professor Linebarger noted that obscene pictures showing naked women, designed to make the celibate troops so desirous of women that they surrendered was a Japanese idea that did not work. “The troops kept the pornography and despised the Japanese as queer little people for having sent it.”

Also found in the article was many soldiers used the leaflets for toilet paper. I bet that was nice for you average joe to have something, anything, to wipe his ass with while stuck in the trenches.