Use instance_eval on @tenderlove's suggestion :trollface:

activesupport/CHANGELOG.md

@@ -1,6 +1,6 @@
 *   Added yield to Object#presence, so you can do this:
 
-      project.account.owner.presence { |p| p.name.first } || 'Nobody'
+      project.account.owner.presence { name.first } || 'Nobody'
     
     instead of calling twice (which may incur double SQL calls):
       

activesupport/lib/active_support/core_ext/object/blank.rb

@@ -40,15 +40,16 @@ class Object
   #   region = params[:state].presence || params[:country].presence || 'US'
   #
   # You can also use this with a block that will be yielded if the object is present
-  # and the result of that block will then be returned
+  # and the result of that block will then be returned. The block itself is run against
+  # the instance you're running #presence on (using instance_eval)
   #
-  #   project.account.owner.presence { |p| p.name.first } || 'Nobody'
+  #   project.account.owner.presence { name.first } || 'Nobody'
   #
   # @return [Object]
-  def presence
+  def presence(&block)
     if present?
       if block_given?
-        yield self
+        instance_eval(&block)
       else
         self
       end

activesupport/test/core_ext/object/blank_test.rb

@@ -35,7 +35,7 @@ class BlankTest < ActiveSupport::TestCase
   end
   
   def test_presence_with_a_block
-    assert_equal "SALLY", "sally".presence(&:upcase) || "Nobody"
+    assert_equal "SALLY", "sally".presence { upcase } || "Nobody"
-    assert_equal "Nobody", nil.presence(&:upcase) || "Nobody"
+    assert_equal "Nobody", nil.presence { upcase } || "Nobody"
   end
 end