In practice, it's fine to age characters who are canonically children to do 'what if' scenarios, such as high school ones.

The issue comes with smut. It's still deeply weird that one would even want to find a 'workaround' to sexualize a child character. It's often made worse when the person aging them up makes no attempts to change their design to reflect that.

Some characters ages will always be debated, which is understandable. Just don't be weird and keep canonical timeskips in mind when you intend to sexually ship two characters.

Make an of-age OC that's inspired by the child character if you really want to explore that aspect of a character. It's honestly that simple.

Not if they have evidence and/or probable cause. Many people fall into the trap of saying 'all callouts are bad' and by proxy defend the likes of abusers on the basis that they 'just want to write' and because 'the rpc is an escape'.

All internet spaces are prone to have bad people in them. Many people get rightfully outed after they get caught with their hands in their pants, and it gives platforms for victims to speak about their experiences and protect any future victims from engaging with the person.

You don't need to reblog every callout you see. You don't even need to engage with them at all. The very least you can do is not demonize every callout. Think about it like this. If your friend called out somebody who has hurt them for years with plenty of evidence, would you not support them? Would you not think the people getting mad at them because they want to write with somebody who harmed someone you care about as irrational?

At the end of the day you're often causing yourself more stress by putting your necks out for proven bad people even though you claim roleplaying is an 'escape' for you. There's plenty of people to rp with but you chose the person who admitted to harming people instead of just... Blocking them? Think about it.

By proxy, you're included on this DNI if you're... Against DNIs. Many people have DNIs and boundaries set for a multitude of reasons. If you don't agree with someone's DNI they wrote themselves or a DNI they linked... Block them. DNIs go both ways. Vagueblogging about people's boundaries just makes you applicable to this DNI at least two times over, mind you. DNIs = People's boundaries. Respect them.

Vagueblogging and guilttripping helps nobody. Not you or the other people involved. The act of vagueblogging comes through specifically talking about one person while not namedropping them (namedropping is still bad in most situations, mind you). Instead, it's better to talk about things in the broader sense. Talk about issues as a whole, not one person. Guilttripping (ie: going 'oh nobody likes me im such a bad writer' when you don't get engagement) is just... A manipulation tactic at best and abusive behavior at worst. There are better ways to ask for interactions or comfort.

When it comes to venting, please understand that your rp blog is not the right platform to do so. If you need a shoulder to cry on, it's best to do it in private. Excessive venting more often than not can be seen as vagueblogging. It's okay to vent from time to time of course, but it shouldn't be consistent.

By proxy, you fall into this DNI if you reblog from 'roleplay salt' or 'roleplay confession' blogs. Those blogs are just platforms for people to anonymously vagueblog others with no repercussions and the posts allow people to vagueblog about others in a more subtle manner.

Just headcanon your character as trans. Not that hard.

Real talk, many people who identify has trans have shown their discomfort for these characters. Many genderbends seem to stress specific binary gender norms (ie: 'genderbending' super mario suddenly makes him a thin tall big boobed woman), and more often are simply a bad idea. The concept is a constantly discussed topic but this is simply an elaboration on why this is commonly seen in DNIs.

Again, many people are simply uncomfortable with this concept and how it's handled within general fandom. There will always be exceptions, just be very careful with the concept if you plan to go through with it, and explicitly state that it's not just a genderbend.

As defined by Merriam-Webster, to whitewash is "to alter ... in a way that favors, features, or caters to white people".

Whitewashing is simply the act of making a character who is non-white white. This is often seen in Hollywood when characters that are black in the source material are played by white actors.

In fandom, the issue is seen when characters are depicted as a much lighter skintone. This has always been an issue in fandom spaces and is just blatantly disrespectful to people of color who deserve to be depicted in media.

By proxy you fall into this DNI if you think 'Blackwashing' exists. Unlike characters of color, nothing is lost when a white character is headcanonned to be anything but.

Incest (yes, adoptive siblings count. if they were explicitly raised together like siblings, even if not by blood, it's still extremely questionable to romantically ship them.)

Pedophilia

Rape (aka non-con)

Zoophilia

Honestly most sexual no-nos you can think of

Akin to whitewashing, it's quite simply erasure. Headcannoning a canonical lesbian to be bisexual just to ship her with men for instance is not only weird but unfair to lesbians, for example.

Mind you, canon is not fanon. Many characters simply do not have a canonical identities and the world is your oyster. But if the character is stressed to be a specific identity, leave that be. Unless it's cishet but you get the memo.