"Prison School" chapter 206 is already online and could be read in English format at My Manga. Chapter 206 is titled "Close Encounters of the Opposite Kind" and it continues the battle of the two student councils. Before discussing the upcoming chapter, here's a brief recap of the latest events.
Kiyoshi is pushing ahead without lifting a finger as he promised to Mari. However, his strength is slowly winding down fast. He asks for help from Mari and knowing that he can't touch them again, he asks Mari to speak dirty.
Mari obliged and later orders Hana to do the same. Mari also asked the help of Meiko to talk dirty to Kiyoshi. Meiko doesn't know anything but confesses all she has are physical enhancements and she is currently wet. Kiyoshi sees the vice president and his vigor comes back for the "final sortie."
The latest chapter indicates that the battle would eventually end through Kiyoshi's effort. However, Kate will not just let them win without doing anything. The Korean scanlations of the upcoming episode are already online through imgur.
The upcoming chapter reveals Kate's preparation for this type of attack from Mari although she noted that she did not expect of Mari use this type of weapon. The Reddit Forum for the manga has the rough translation of the upcoming chapter.
Kate responds by sending "Gyaru Riders" and they immediately display their capability. They are not intimidated by the power of Kiyoshi. They are in fact, interested on what Kiyoshi displays but the riders kicked him in the groin.
The group also seduced Kiyoshi as they ask him to come over so he could feel them. Kiyoshi was about to leave when Mari orders Meiko to grab him. Meiko did grab him but she grabbed his manhood which invigorates him. Hana then kicks him from behind that eventually lowers his underwear. The final showdown is about to begin as Kiyoshi will be in full force for the attack.