class ActiveRecord::Reflection::ThroughReflection

taggings_reflection = tags_reflection.through_reflection
tags_reflection = Post.reflect_on_association(:tags)

end
has_many :tags, :through => :taggings
has_many :taggings
class Post < ActiveRecord::Base

of a HasManyThrough or HasOneThrough association. Example:
Returns the AssociationReflection object specified in the :through option

def through_reflection
  @through_reflection ||= active_record.reflect_on_association(options[:through])
end