User blog comment:Miskos3/Fairy Tail Chapter 508: Pleasure and Pain, Review/@comment-24784846-20161102033214

Copypaste.

Honestly, many have jumped to the conclusion that Larcade's magic affects those who have lost their virginity, but upon closer inspection, I believe this is simply a misinterpretation.

Now let's go over Larcade's definition:

''Larcade: My magic is 'pleasure'. It is impossible for those who have already tasted the forbidden fruit of pleasure to escape from my magic''

Now many assume that the forbidden fruit of pleasure refers to sex. Banging. Scoring. Bonking. You get the jist of it. However, the term "the forbidden fruit of pleasure" actually derives from the biblical story of Adam and Eve and while it is often used as an allegory for sex in literature, it isn't necessarily associated only with copulation. "The forbidden fruit of pleasure" is a metaphor for any kind of immoral action that causes pleasure according to Christian belief. This can include non-reproductive sex (sex for pleasure) but also other actions such as killing, betraying or harming others without regret or other actions deemed immoral by the church. From wikipedia:

As a metaphor, the phrase typically refers to any indulgence or pleasure that is considered illegal or immoral.

Note! Forbidden Fruit of Pleasure was a change included by mangastream. The original raw text refers to "that taste" or "it's taste" without really specifying what he is referring to. It is left vague on purpose, but never really refers to anything related to sex. (Chaos can correct this if my sources are wrong on translation) More insight in the comments below Even Mavis first thinks that it is related to sex, but then realizes it isn't Mavis: Only the adults are falling one after the other... No! That's not it! This puts many characters into a much more logical perspective (though please keep in mind that the concept of what is and isn't "sinning" is quite subjective in religion):


 * Sorano: Killed Karen Lilica among others during her time in Oración Seis without feeling remorse
 * Yukino: Unaffected as she never has commited "evil" actions for pleasure
 * Minerva: Tortured Lucy among other things, feeling satisfaction from those actions
 * Rogue: This probably has to do with his inner shadow (which might be why he doesn't feel it immediately and his reaction is slightly different than Minerva's, as he clutches his heart). We've seen what his inner shadow has made him do later on as Future Rogue
 * Alzack and Bisca: Sex for pleasure (considered a sin by the church). You could also count Bisca's actions as Moulin Rouge
 * Macao: Very perverted
 * Max: could be unknown, though technically any kind of sexual interaction with an object is a sin and he looks pretty damn pleasured by it
 * Wakaba: Same as Macao
 * Laki: Has shown sadistic and masochistic tendencies (remember her room)
 * Romeo and Asuka: Haven't ever sinned for pleasure, pure children
 * Laxus: His arrogance has led him to betray his guild, proving great pleasure and satisfaction from it
 * Warren: Unaffected, has never really sinned
 * Mavis: With her curse she has taken the lives of many because of her love for others. While not exactly "pleasure" for killing, it is her love (and the pleasure that comes with it) for others that has caused their deaths
 * Gildarts: Banged with more women than stars in the sky
 * Cana: Seems like she hasn't sinned. Considering that she's still 19, it's not that absurd to think that she hasn't lost her virginity yet (her saying that she needs another boyfriend was only in an omake confirmed to be non-canon). While there is some debate about getting drunk being a sin, the bible does heavily suggest not to. That said this is a debatable point since wine was heavily used instead of water back in older times, for several issues such as contamination of water. And there's also the whole fact that wine is supposed to be the blood of Jesus and how it is heavily tied with religious ceremonies - but that's going too much into religion.
 * Crime Sorcière: They all have sinned but they don't seem to be affected because they are unconscious. We also don't see any of their faces clearly, so we can't really tell. We only get a glimpse of Jellal (only his mouth), who could also be justified by the fact that none of those actions were caused by free will. Being possessed is not a sin in religion
 * August: Has shown to be wise and kind, which would explain why he is unaffected. He doesn't seem to experience pleasure in fighting others. He defended Ajeel since he "would've grieved his loss" and also accepted Brandish's negotiations to stop his attack on Fairy Tail
 * Irene: On the other hand, Irene obviously has taken great pleasure in torturing others
 * Erza and Wendy: Despite their difficult pasts, they have never sinned
 * Zeref: Same reason as Mavis

Let's also consider Irene saying "To think that Larcade's magic wouldn't be effective on either of you", it obviously doesn't refer to "Wait, you mean that Wendy ISN'T a virgin???!!!". It just simply means that she is annoyed by how pure their hearts are (remember when King Toma said that he still loved his daughter even if she was a rat, Irene was annoyed by his kindness. She dislikes kindhearted people in general)

So yes, Larcade's magic, "Pleasure", affects those who have experienced pleasure from an immoral action, causing them to feel a strong feeling of euphory which leads to death. He also possesses a short-range version that can affect even those who haven't sinned. Not necessarily tied with boning…

but who knows, really, it is Mashima.