There really is only one hard and fast rule.
"Don't Be a Dick."
It's quite simple. Do what you want, have fun, but don't offend, harass, menace, intimidate, or discriminate against others on the site. If someone tells you what you're saying crosses their boundaries, stop. Freedom of speech does not equate to freedom from consequences, nor is anyone else required to provide you a platform.
Don't be a dick also means don't come running to the admins every time you disagree with someone. We are all adults; respect each other, respect yourselves, respect a little common courtesy too.
The usual chat rules regarding children, public sexual content, etc. apply here. If you really can't help but want to explore such themes, take it elsewhere. We don't want to know about it.