BattleSexer Seishiro

It is the 23rd century, an age of science and technology, where sex is no longer required to reproduce. However, humanity has not forgotten sex! Sex has evolved to become a form of martial arts, and those who practice it are known throughout the world BattleSexers!
Published in Young Magazine the 3rd, Vol. 4 in 2015, as part of their "Ore no The 100th!!" series, where well-known manga artists attempt to write the 100th chapter of a manga without the other 99.