victory lap

noun4

1. •
   A celebratory extra lap of the race track taken after the conclusion of a race.
2. •
   (figurative) An act of pride or celebration that follows a great achievement or success.
3. •
   (US, slang) One or more years of study beyond the traditional four taken to complete one's undergraduate degree.

   • It’s not just finances that lead to victory laps. Those who study abroad during undergraduate may find it difficult to earn enough credits to fulfill degree requirements in four years. — 2013
4. •
   (Canada, slang) One or more additional years of study in high school.