How to add RDoc documentation for a method defined using class_eval?

I am using class_eval to define a bunch of repetitive methods more concisely, something like this:

%w{greasy chunky bacon}.product(%w{flying sky poodle}).each do |a,b|
  class_eval "def #{a}_#{b}; do_something; end"
end

I would like all the resulting methods to be included in the RDoc documentation. Is there an RDoc directive which "manually" adds a method to the list of methods for the class? I can't find one.