Well....
You'll have to ask directly a staff member to make sure your content is not breaking any guidelines. Or if you have to put a mature filter.
In most cases on Webtoon Canvas, you cannot post anything that its too graphic nor suggestive.
I believe this mini page strip made by ArtOfAmontillado on Spiga-Rose's case (You can see all their experience) with the staff editor, Reno; would gives you an idea about how they are.
I must have to mention, most of the time you'll receive automated answers, not real people specifically checking your work. As far as I know, we Canvas creators are not allowed to show nudity, nor use mosaic censorship, nor black boxes (We have to make ""natural"" censoring), as well pantyshots, female cleavage, nipples, too thight clothes are mostly not permitted.
The Originals may have a bit more of freedom, but its absolutely out of question to try to mimick what they do despite an editor already worked and approved their content. Webtoon has double standards regarding guidelines as well...
There are cases that they will reject your Ad Revenue for mature content, whilte they claiming the do check the chapters during the revision period, but, when it comes to tracing and plagiarism they are blind.