In practice
Tilt is the point at which frustration, anger or euphoria is making the decisions. The term comes from poker. Its signs are physical and behavioural: tension, clicking faster, ignoring the checklist, increasing size.
Traders learn their own early signs and act on them at once: close the platform, leave the desk, and come back only after a proper break or the next day.
What to watch for
People on tilt rarely believe they are. That is why the rule has to be set beforehand and tied to something that can be measured, such as a number of losses or a loss limit, not to how you feel.