where it counts

adverb3

1. •
   in the most advantageous area or sphere

   • True, Madeline does not have a lot of book smarts, but she is plenty wise enough where it counts.
2. •
   in an effective manner

   • At first the boycott's impact was barely noticeable, but now the protesters are hurting the store where it counts.
3. •
   (euphemistic) in the testicles

   • A girl's best weapon — and one that should be used sparingly — is a swift kick where it counts.