Rap is the language of a man's soul is the fifth episode of Gurren Lagann Parallel Works.
The story begins with Gimmy walking naked through the terrain until he comes across a goofy version of Simon bottomless and waving. Gimmy sticks his finger in Simon's tight butthole, causing him to fly out of his trademark jacket. With that, Gimmy takes the jacket and leaves Simon naked as he continues his walk cycle. The scene then goes to Kamina passing Gimmy which soon after, the latter poked Kamina in the anus as well and took his cape and sunglasses. Finally, the bodacious Yoko Littner walked along the terrain until Gimmy creeped up behind her. He was about to poke her in the rear until she stopped walking and gave Gimmy an intimidating look. Gimmy starts to walk away but then he distracts Yoko and snatches her bra. This causes Simon, Kamina, and Yoko to go after Gimmy in Gurren Laggan. They have Gimmy on the run until Gimmy poked the backside of Gurren Laggan, causing it to explode. The episode ends with the scene shifting to a nude Gimmy actually dreaming the events in his mind. The end.
This is one of the two times they show Yoko's nipples.
This parallel work is likely inspired from the director's cut of episode 6 of Gurren Laggan "There are Some Things I Just Have to See!!" when Gimmy mistakenly poked Simon in his anus and Kamina urged him to do the same in an attempt to see the girls nude on the other side of the hot spring. A couple of scenes from that episode are seen in this parallel work as well.