consent on the floor
a dark room is not permission. it never was.
Being in a club is not consent. Dancing near someone is not consent. What someone is wearing is not consent. Smiling at you is not consent. Being on something is not consent, and in fact means the opposite: someone who is altered cannot give it.
Consent is someone actively, clearly wanting the thing that is happening. If you are not sure, you do not have it.
Ask, out loud. The music is loud, so lean in and ask. It takes two seconds and it is not unsexy. Reading body language across a strobing room is guesswork, and guessing wrong is not a small mistake.
Read the no. Turning away, stepping back, moving to another part of the floor, a friend inserting themselves between you. These are all a no. They do not need to be said.
Give people room. Nobody should have to negotiate their way past your body to get to the bar.
If you see it happening, do something. You do not need to start a confrontation. Step in between. Ask the person if they are alright. Pull them into your group. Tell security. Doing nothing is a choice, and it is the one that keeps the problem here.
If someone tells you they have been touched or followed, believe them and act on it. That is the whole job.