ziggy_Z said:
So someone on /r/FairyTail fabricate some not-sicko theory that has some logic to it.
https://www.reddit.com/r/fairytail/comments/5afnfm/ms_why_this_chapters_magic_might_have_absolutely/
TL;DR Pleasure = biblical pleasure; not just limited to pre-marital sex, but sadism, etc.
HOPEFULLY (even though the chances are slim) the pleasure refers to sins committed in the past. Like Rogue falling to Darkness, Minerva torturing Lucy, Zeref and Mavis being cursed by Ankhseram etc and those who have not committed any sins will not be affected by it but even then this chapter will still be hilarious (in a bad sense) IMO.