This is the question almost everyone outside the community asks first, and it deserves a real answer rather than a defensive one. The difference isn't how something looks from the outside. Restraint, impact, or a Dominant/submissive dynamic can look intense either way. The difference is what's underneath it.

BDSMAbuse
Agreed to in advance, by both peopleNot agreed to, or agreement is ignored
Can be stopped at any point, by either personContinues regardless of what the other person wants
Has limits that are respectedLimits are pushed or disregarded on purpose
Followed by care and checking inFollowed by fear, isolation, or control outside the dynamic
Exists alongside the rest of a healthy relationshipIs used to control the relationship itself

The tell that actually matters

A safe dynamic has an "off switch" that works, every time, without punishment for using it. If a safeword gets ignored, if "no" during a scene doesn't stop the scene, or if bringing up a limit afterward gets met with anger instead of a conversation, that's not BDSM anymore. That's the definition crossing over.

What if I can't tell whether something that happened to me was BDSM or abuse?

Ask yourself one question: did you agree to it, and could you have stopped it? If the honest answer to either is no, what happened to you wasn't a BDSM dynamic — it was something done to you without real consent, whatever language was used to describe it at the time.

Consent isn't a one-time checkbox either. It's the ongoing thing that separates the two columns above, which is why how a platform actually handles safety and verification matters more than how experienced someone claims to be.