Info on Sex Pistols
This manga is licensed in R1 under the name "Love Pistols". You can purchase hard copies at amazon and the usual spots, and it is also digitally available (up to volume 9) on comixology.
Because the anime for Sex Pistols does a terrible job of explaining the mythology and what's happening in the show, here's a writeup explaining things. Also please note that the translation in the anime is suspect, and not everything explained in the anime is right. Also this will not include the extra characters and plots from the manga that never appeared in the anime.
Characters: Everyone in this story is a high schooler.
- Tsubaraya Norio (1st year, catboy/domestic, retrograde*, "the spaz")
- Madarame Kunimasa (2nd year, catboy/jaguar, heavy seed, half brother to Yonekuni),
- Kumakashi Teruhiko (3rd year, bear/asian moon bear/light seed (anime), bear/asian black bear/medium seed(manga), "flower boy").
- Madarame Yunekuni (3rd year, dragon/crocodile, heavy seed, half american/half japanese, "hot swimmer guy"),
- Fujiwara Shirou (3rd year, dog/wolf, heavy seed, "class rep").
- Aogiri Oushou (3rd year, snake(anime)/dog(manga)???, medium seed, friend of Shiro's who is in love with him).
- Joshua McBear (1st year (equiv), bear/grizzly, heavy seed, old acquaintance of Teruhiko, american)
Madararui: People not born as monkey base types. Most humans are monkey base types. Their "power" is super high fertility and they cannot sense madararui. Madararui being non-monkey base types have trouble breeding (low fertility), thus the shenanigans of the story. The Madararui consist of dogs, cats, snakes, bears, dragons, and mermaids (not shown). They seem to have both primary types (ex: cats) and subtypes (ex: jaguar). They seem to be able to take on full and partial forms of their subtypes (hence fully transforming into a cat or dog sometimes, or having ears/tail while still in humanoid shape), usually when under a lot of stress or during times of high emotions. Both guys and girls can be madararui, but it seems like this story focuses on all dudes.
Seeds: Heavy, medium and light seeds. This describes both their power level and their fertility rate, and to some degree their distribution among the general populace. Heavy seeds are powerful but they have the worst fertility and distribution rate of the three. Normally heavy seeds would be paired up with light seeds or retrogrades to promote reproduction. Light seeds have the highest fertility of the madararui (although nowhere near monkeys), but they are the least powerful of the madararui. The story seems to equate heavy seeds with tops/semes, and light seeds with bottoms/ukes. It seems like certain subspecies are always specific seed types (Shirou is said to be a wolf subtype, which are all heavy seeds; Joshua is a grizzly, said to be the "heaviest seeds" of the bear type).
Retrograde*: These are basically "mudblood" madararui, although rather than being outcasts they are extremely rare and greatly sought after. Essentially they are monkey types who have madararui blood somewhere in their ancestry, but it is latent. Typically something will happen that will suddenly awaken their madararui blood. When this happens, they gain both their madararui powers AND retain the super powerful fertility of their monkey blood (although most usually go insane). Norio (a spaz, but not insane) is the primary retrograde of the story, and everyone is after him because if they "breed" with him, they are effectively guaranteed to propagate, which is not true of other types of madararui, even light seeds. Note: this concept is translated several ways in the various media, I went with "retrograde" because I liked this one the best. (Return to Ancestry is another name for this, but it does not roll off the tongue well and fits poorly into the dialog).
Plot: Generally speaking, the madararui try to start breeding as early as possible because it's so hard to propagate, which is why the incessant nagging about it from various people in the story. They can either have studding done (like with Teruhiko) and hope something takes, or sometimes madararui can mate for life in a permanent bond kind of way. Usually, the light/bottom/uke is the one that chooses, since they typically have multiple heavys/mediums after them because of their fertility rate. Once a mate is found, they can use various of their powers to exert influence over each other, hence all the stuff about Kunimasa helping to get Norio's excessive soul libido aura under control.
Most madararui have "powers" that give them a leg up on the monkeys, but occasionally there are downsides. This is where the reptile types' inability to control their body temperature comes in to play. Yonekuni has this issue excessively badly because he has two reptile parents (snake from mother, dragon from father). His dragon side is dominant, but he is doubly affected by the inability to control his body temperature. Meanwhile, dog types like Shirou are said to have high body temperature, which is why both reptile boys in the story (Yonekuni and Oushou) are after him - Shirou has the ability to keep their body temp regulated.
Norio also has a significant ability to see the base types of all people, monkeys and madararui. Most madararui do seem to have some ability to see this too, but Norio's ability is especially powerful. I am unable to determine if this is an ability he gets from his catboy/madararui half, or if it's specifically because he's a retrograde. Either way, this is why he was able to tell that Shirou was not a monkey. Also, since most madararui have this to some degree, this is why Yonekuni was able to tell a couple different times that Shirou perhaps wasn't a monkey type, but because he was zombie'd out when he noticed this, he never remembered it or wasn't quite able to figure out what Shirou was if he wasn't a monkey.
In terms of the Shirou/Yonekuni story. (This story is muuuuuch better in the manga - they cut out so much in the anime) Because Yonekuni is a reptile type, he cannot well regulate his body temp. He specifically has more trouble with this than the usual reptile type because both of his parents are reptile types (snake/dragon) whereas, for instance, his half-brother Kumimasa is the child of a snake/cat (so doesn't have this problem, esp because his cat side is dominant). Anyway, because Yonekuni has trouble regulating his body temp, and because he's a heavy/alpha male, he's kind of a manslut and screws girls he doesn't care about all the time to help regulate his body temp. No explanation as to why he can't stand guys (*correction: in the manga this is explained, and basically boils down to daddy issues). During the rainy season in Japan, whenever it rains, he goes into this catatonic trance, this zombie-like state, where his subconscious is in control and his consciousness is asleep. The things he does or that happen to him in this state he can't remember. Back when he was in middle school, he collapsed in the locker room due to body temp issues and someone appeared to save him. It was a dude, a dog/wolf madararui, but Yonekuni didn't know who. Yonekuni realized he was attracted to this person at the time, but couldn't recall who it was. Everyone thinks he imagined it. He has always gravitated towards dog madararui since then, guys or girls.
Well later, during their second year of high school, Yonekuni collapsed at a school event due to the body temp issue and he was taken back to Shirou's house. Because Shirou could regulate his body temperature, Yonekuni's subconscious recognized that he could always go to Shirou if he was in danger of dying from low temp issues. Thus, whenever it rains and his body temp gets dangerously low, Yonekuni goes to Shirou's house in his zombie state to get his temperature regulated by Shirou. At some point, instead of just effectively "cuddling" to get his body temp under control, he pressures Shirou into sex due to his aggressive nature. Because Shirou was already in love with his dumb ass anyway, he just let him do it. After it happened once, then every time after that, Yonekuni would come over when it rained to have sex with Shirou. It's a bit ridiculous that this series somehow managed to put both Shirou and Yonekuni simultaneously into a rapey situation with each other. Does it cancel each other out? I can't even figure it out.
During the "present day" of the manga/anime, Yonekuni acts like he just tolerates Shirou while he subconsciously goes out of his way to be around him and get between him and Oushou, etc, although he doesn't seem to realize he's doing it. Kunimasa, Yonekuni's little bro, was in on this the whole time too because Shirou seemed to be able to easily bring Yonekuni back from the brink during these times of dangerously low body temp. Kunimasa's speech to Shirou at the gate made it clear that Kunimasa actually knows a lot more about all this stuff than anyone else (in the opening of the anime, recall, he says he's just bad at explaining it). He was able to see that his bro was in love with Shirou waaaaaay before Yonekuni ever had to face that reality. Shirou was unable to see it because he was infatuated and didn't really live in the world of the madararui even though he was one, so he just didn't have the background info Kunimasa (et al) did regarding the society of the madararui. The anime leaves out a lot of Yonekuni coming to terms with the fact that not only does he love Shirou, but that he finally put two and two together (Shirou was the one who saved him in middle school). And that he gravitated toward dog types. AND that madararui often had love at first sight experiences (that bond thing), admitting to himself it was probably Shirou. This set of realizations happens during that montage before Shirou goes to school with Kunimasa and has to climb the fence. There is a shitload more stuff left out of the anime that makes this situation a lot more gratifying.
If you're interested enough at this point, just read the manga on mangago.me