Question about scope when using `exend ModuleName` and `::define_method` in a class

extend_module.rb

module M
  def i_method
    define_method(:new_method) do
      "I am from i_method, but I should be an instance method"
    end
  end
end

class C
  extend M

end

C.i_method
C.new.new_method

# The arguments that would also work on line 3:
# self.send(:define_method, :new_method) do
# send(:define_method, :new_method) do

# What is going on?
# I thought `self.define_method` and `define_method` would be the same?