Your Abs won't be Ripped but Your Ass will be is the 600th chapter in Gintama. Negotiations continue as Nobu Nobu struggles with both his stomach problems and one of the Army's leaders.
After asking to use the bathroom again, Nobu Nobu is coldly forced to remain seated by Katsura and Sakamoto, telling him that it's do or die for him and the Earth. A figure arrives and bluntly asks that Nobu Nobu wishes for the Army to leave the planet. Katsura reveals that the Amanto, Shijaku, was both a Liberation Army founding father and a powerful Admiral; the trio now has a chance to speak directly to one of the leaders. Shijaku responds that they can't leave as the Tendoushuu was not just Earth's problem. To break their tyranny was the long desire and ideal for the people of the universe. He adds that it would be a better idea if Earth allies with them and wonders if they will work with the Tendoushuu instead. He mentally understood that the Altana group had controlled the bakufu for a while and was lead to believe that the government can no longer stand up for themselves. The fact that they were here made the admiral reconsider, but he misinterprets Nobu Nobu's bowel struggles as fear in dealing with the army's might. He out loud asks if Earth will join them in winning their freedom while mentally demanding that the Shogun gives in to his fear and accept his continued existence as a puppet.
Nobu Nobu answers that the army's "freedom" was more to steal the others freedom to benefit themselves. He declares that the samurai fight for true freedom, which is to use the bathroom anytime he wants (another attempt for a bathroom break). The fearful shogun is coldly told to stay by Katsura and Sakamoto again and the Admiral is surprised by Nobu Nobu's "confidence". He asks if they will join the Tendoushuu but Nobu Nobu cries out that Earth will not work with the Army and will fight them if they plan on trying to conquer Earth themselves in "cooperation". Nobu Nobu quickly tries to end the negotiations to head to the bathroom but is again coldly stopped by Sakamoto and Katsura, while Shijaku wonders what Nobu Nobu is truly afraid of. Shijaku calls out to him but Nobu Nobu declares that he will "fire" if the Army keeps him here longer. Falsely believing that he may have real weapons, the Army surrounds the three humans. Shijaku tells the men to stand down and asks if "it" was his last resort. Nobu Nobu exclaims that the army forced him into this position, that he can no longer stop it, that it will be a stain that will stay with him even beyond death and they have three minutes. The army misinterprets his statement into having a nuclear weapon and stand in fear. One of the soldiers believes that Nobu Nobu had the "weapon" in his stomach, something powerful that the Samurai held called the "Bowelcut", in reality he is about to take a dump. Some of the soldiers try to stop the shogun and are knocked out by his fart. The army panics and Shijaku tells them and all other ships to stay far away from the main ship, Amenotori.
But he decides to stay, saying he respects that Nobu Nobu was planning to risk his own life to save his planet. He chooses to risk his own life to stop the shogun by using the "reverse bowelcut". After taking a dump, Shijaku realizes that he had misunderstood the situation and asks that Nobu Nobu not tell the oblivious army he messed his clothes and in turn they will do proper negotiations. Nobu Nobu then asks Katsura and Sakamoto, who also remained, could he finally use the bathroom. They agree and pat him in the back, which unfortunately results in Nobu Nobu finally taking his own dump. Later, Sakamoto and Katsura tell Shinpachi about the "negotiations" and its results: Shijaku became a valuable ally, the Edo rebellions ceased and the rampaging army were disciplined but they weren't withdrawn from Earth. The two asks how well did they do but the agitated Shinpachi responds that it's poop while crushing the radio.