Applying custom parser on save only

[noctivityinc]

I created a custom parser to remove the # sign from the start of any tags that a user enters in:

class NoHashTagsParser < ActsAsTaggableOn::GenericParser
  def parse
    ActsAsTaggableOn::TagList.new.tap do |tag_list|
      tag_list.add @tag_list.split(',').inject([]) {|res, tag| res << (tag.starts_with?('#') ? tag[1..-1] : tag)}
    end
  end
end

ActsAsTaggableOn.force_lowercase = true
ActsAsTaggableOn.default_parser = NoHashTagsParser

So if they enter in "this,#is,a,#test" it will save it, correctly, as [this,is,a,test]. that works fine. However the parser seems to get called every time I want to loop through the tags as well, which results in an error like this:

undefined method `starts_with?' for ["testing"]:Array

how can I have a custom parser that works on save only?