What is it?
Aqiqah is a recommended sunnah on the 7th day after a child's birth: one goat / sheep for a girl, two for a boy (or one share of a seven-share cow per child). The meat is divided into thirds, for the family, for relatives and friends, and for the poor.
If the 7th day is missed, the Aqiqah can be performed any time afterwards, even into adulthood.