The stage you are referring to is called "tolerance." In the context of alcohol consumption, tolerance occurs when a person needs to consume more alcohol to achieve the same effects that they initially experienced with smaller amounts. However, "reverse tolerance" can also refer to a situation where a person becomes more sensitive to a substance, needing less of it to feel its effects, typically associated with increased intoxication or sensitivity, often seen in individuals with liver damage or other health issues.
In your case, since you mentioned needing less alcohol to feel intoxicated, "reverse tolerance" would be the correct term. However, it's important to clarify that tolerance refers to the need for increased amounts, while reverse tolerance indicates increased sensitivity.