victory lap

Short definition from Wiktionary

Noun

1. 1
   A celebratory extra lap of the race track taken after the conclusion of a race.
2. 2
   An act of pride or celebration that follows a great achievement or success.
3. 3
   One or more years of study beyond the traditional four taken to complete one's undergraduate degree.
4. 4
   One or more additional years of study in high school.