If you're looking for manga similar to High School DxD EX (Light Novel), you might like these titles.
The Main Character finds himself at a beauty salon that acts as a front for succubi to gather semen as food to send back to their world and it turns out that the Main Character’s high libido and special cum might be able to save the succubus world from decline.
Kusaku Kouichi is a highschooler who is somewhat uncomfortable with the eros due to his older sister being a manga artist for erotic mangas. Aside from being dragged into the whims of his free-spirited sister, he led a pretty average lifestyle until the summer break of his second year in highschool, when his life met its turning point. He found out that his childhood friend, Mia was actually a succubus who did not know her stuff, and that she would be in deep trouble if he does not teach her how to do the dirty deeds. Furthermore, in a twist of fate, all the girls around Kouichi were clueless succubuses similar to Mia—The erotic love comedy of “teaching” his harem starts now!
Ai Shiratori is your average junior high school student with a crush on a boy, Hikaru Kamishiro. With a love so rampant and true, and an imagination as wild as any girl's Ai sometimes has rather... ecchi dreams. But none of those dreams could ever prepare her for the reality that came to her in the form of the Archangel Raphael. You see, Hikaru Kamishiro is not your average boy. Hell has plans for him and Heaven isn't about to let those plans come to fruit. While Hell sends their Hell's Apostles to get Hikaru to commit the seven deadly sins and drag him into hell, Heaven sends their secret weapon: Ai. What is Ai's mission? Nothing short of consummating her love with her beloved Hikaru... but wait by consummating you mean... sex?! Can Ai handle the Archangel's request and save her true love?
Morioka Yuuto was an ordinary highschooler who was chosen as a candidate for the next Demon Lord. Thus, he was transferred to a Demon’s school, Ginsei Academy where he faced contempt from the other students. “—I’ll make you into the Demon Lord. So…… take me.” Through an encounter with the Demon beauty, Himekami Rizel, Yuuto’s life changed, along with the world. In addition to being able to learn any magic at one glance, he can also infinitely absorb the mana of his harem by maintaining skin contact. This was the special ability which can only be held the human Yuuto. The human Demon Lord candidate aims to become a just Demon Lord and stand against the strongest Demons!