How many of us jump at the sound of a leather belt being slid out of the loops of a man's pants...
I can think of so many scenarios that might be the set-up for. What comes next? Unbuttoning the pants, or the doubling of the belt so that it aims better? If you have been ritually abused in this way, your skin is crawling and you know what comes next. I think I expect either one.
Ritual abuse is any repetitive pattern of abuse. Again, like so many things in the world, it comes in matters of degrees. For that sound of the belt to be a trigger you didn't only go through a pattern once -- it happened many times. It was predictable what the outcome would be.
To go even further into ritual abuse, some abusers set up deliberate patterns, or ritualize the abuse. Perhaps it even has the trappings of a religious ceremony. The same problem happens -- any of the points in the ritual become part of the trigger, or the places you were taken, the items worn or in the area -- everything becomes a warning that someone is about to hurt you.
Both the incidental and deliberate ritual abuses can cause problems when trying to heal. They are very ingraned, entrenched patterns.
Self-help note: Carefully exploring a trigger and NOT having it followed by abuse and pain can help cause "extinction" of the trigger. However, the triggers are very likely to come back full force on short notice should the scenario(s) happen again, so this is often difficult. If you find yourself trying to deprogram triggers caused by ritual abuse, the extinction scenarios should be managed very slowly and carefully to avoid re-triggering the responses.