BUR #515 is pending approval.
remove alias foursome -> group_sex
create implication foursome -> group_sex
I come back from my vacation with a proposal for moving away from Danbooru traditions. I've always found the foursome alias to be unhelpful. The reason is that I think a foursome is an easily identifiable form of group sex that deserves to stand on its own. Posts like post #74950 or post #93750 are neither gangbangs or orgies, they're foursomes, 4 characters having sex while "connected".
Since there's no need to do everything exactly as Danbooru, I think it's better to do away with this alias. Not so much with fivesome because that one bleeds a lot more into regular gangbang.