The Secret Devil-chan

Kurosaki Sou is a 16 year old who has never been good with girls, every girl he has tried wooing for has been taken away from him by his best friend Haida. One day, Haida's bragging really angers Sou, so he says he'll get a girl. Haida says that the only girl he could get would have to be an alien, angel or devil. Blinded by anger, Sou claims that he will, in fact, get with an alien, angel or devil. His attempts at getting abducted unsuccessful, Sou summons Kogure, a succubus, to take his virginity. However, Sou finds out that Kogure happens to have a penis. Sou, not taking the news well, manages to escape, but he finds out that Kogure can't go back to Hell until he fulfills their pact, and that Kogure will be living with him and going to school until then. Hilarity Ensues.

The Secret Devil-chan is a manga in the Otokonoko Genre by Emu. Currently completed at two tomes, was published in America by Digital Manga Publishing. It has a sequel, appropriately titled 'More! Devil-chan, that continues the misadventures of Sou and Korure; this one is also concluded in 16 chapters.

Tropes used in The Secret Devil-chan include:

A Man Is Not a Virgin: The reason Sou summoned Kogure. He decides he can wait after he finds out that Kogure isn't just using male pronouns to sound cute.
Beach Episode: Happens in chapter five, but Seira makes everyone collect the garbage on the beach.
Black Comedy Rape/Double Standard Rape (Male on Male)/Double Standard Rape (Female on Male):
- Kogure tries this on Sou, but quickly gives up. He spends the rest of the series trying to seduce him by way of Fan Service instead.
- Haida is completely okay with Kogure licking the spilled milk off of Seira's breasts. Seira, not so much.
Blue and Orange Morality: Since demons do not categorize gender the way humans do, Kogure is just unable to understand why Sou doesn't want to have sex with him after the "reveal".
Casanova: Haida would always woo the women Sou was after ever since they were in kindergarden. This is subverted when Kogure ignores his advances because he likes Sou.
Childhood Friend Romance: Sou and Seira. Although Sou insists that it's not like that.
Covert Pervert: In chapter four, Kogure tells Seira that, deep down, she's as perverted as anyone else, and reacts the way she does to Kogure's shenanigans toward Sou out of jealousy.
- Inverted with Sou, who believes that he should be honest with his thoughts so that people can see he has nothing to hide.
Determinator: Haida is fixated to the point of obsession on wooing Kogure. Arguably, Kogure himself towards Sou.
Devil in Plain Sight: Kogure enrolls in school under the surname "Deimon."
Did Not Do the Research: Succubus is never purely male, they are either capable of changing their gender at will or more traditionaly they are completely female while their male counterparts were named Incubi.
Dropped a Bridget On Him: Sou realizes too late that he should have put "a vagina" on his succubus wish-list.
- And to the entire class in chapter three. Kogure doesn’t like to wear underwear.
Dude Looks Like a Lady: Kogure of course, not that his clothing choices help.
Even the Guys Want Him: Sou seems to be the only guy in his age group that's not eager to jump Kogure's bones, whether they know his real gender or not.
Evil Redhead: Kogure. Well, he is a demon who doesn't have many qualms about brainwashing people for his goals.
Every Girl Is Cuter With Hair Decs: Seira has wing shaped hairclips.
Finger-Suck Healing: Kogure claims that Sou's been teasing him with that bleeding hand of his and begins licking it.
Girl-On-Girl Is Hot: Seira spills milk on her breasts. Kogure, not wanting the milk to go to waste, starts licking it off. Haida sits back and enjoys the imagery, Seira's pleas for help being ignored.
Green-Eyed Monster: The entire plot happens because Haida, Sou's childhood friend and resident Casanova, was bragging about how successful he was with the ladies and Sou wanted to lose his virginity by any means to shut Haida up.
- Kogure is jealous of Seira when Haida says Sou and Seira are having a “lover’s quarrel”
- Every male student is jealous of the attention Sou gets from Kogure.
- Seira may or may not be objecting to the overtly sexual anecdotes Kogure spouts about her and Sou out of jealousy.
Japanese Christian: Seira
Kissing Cousins: Since Kogure's assumed identity until he fulfills his contract is Sou's cousin, all his flirtations with him (Along with the kinky stuff like declaring that he wants to drink his semen the most) give the appearance of this.
Mind Control Eyes: Kogure has this power as a succubus, and he uses it on everyone from Sou’s parents to a Cashier at the Grocery store.
My New Gift Is Lame: Subverted, Kogure likes the seashell necklace Sou gave him in Chapter 5, even though Sou feels guilty for only giving his a necklace of a seashell he found, and Seira hung on to the one he gave her when they were younger.
Noodle Incident: In the first chapter, Sou says he tried summoning after his attempts at getting abducted didn't work out. God only knows what those attempts involved.
The Tease: Kogure’s character in a nutshell
Super-Deformed: Happens fairly often throughout the series.
Zettai Ryouiki: The School uniforms and Kogure’s outfit.