How to add method called after another method in Ruby

There is a class that has many methods, all returning string(url). I want to add new method called after any of the previous ones, which adds extra parameter to url. Example would be :
Class.method.my_method
returning
www.domain.com/xxx/xxx?my_method_return
What would be the best way of doing this?

Also is there any source where i could find solutions for similar problems? I posted it here as I'm not sure where else I could look for answer.