That's something you'd have to ask Michael, not me lol Although, I still feel inclined to tell you this:
With Tapastic's app, which recently became available on the Apple Store for iPhone's and such, they (as in the owners and staff of the website who were responsible for building the app) had to agree to certain terms and conditions to allow their app to stay on Apple's servers and in the Apple Store. Some of these terms included what kind of mature content is allowed and not allowed, as they would technically be representing Apple.
Anything that's considered "inappropriate", or better yet, NSFW, has to be behind what we all know as the NSFW filter. This is to follow general laws with exposing minors to 18+ content, as well as the rules of Apple as a company that hosts Tapastic's app, which also has to follow these rules and laws.
So if your content - which if it's 18+, so I'm hoping that it's behind some NSFW filter to begin with where it's needed /cough cough - was featured on the front page, it would still need to be bypassed by readers saying they are 18+, plus that could fall back on Tapastic as an iOS app and could cause problems for them hosting their app in the future.
Of course, this is all speculation on my part from my general knowledge of the subject. @michaelson would be able to answer it a lot better than me and I'm sure he could tell you what may or may not happen regarding your concerns about this