The most resonating case of an object that is a descriptor is probably a function. Functions implement the __get__ method, so they can work as methods when defined inside a class.
Methods are just functions that take an extra argument. By convention, the first argument of a method is named "self", and it represents an instance of the class that the method is being defined in. Then, whatever the method does with "self", would be the same as any other function receiving the object and applying modifications to it.
In order words, when we define something like this:
class MyClass: def method(self, ...): self.x = 1
It is actually the same as if we define this:
class MyClass: passdef method(myclass_instance, ...):