Sometimes emergency contraception is needed to prevent pregnancy after sex - for example, if the pill is missed, a condom breaks or in the case of being sexually assaulted. The morning after pill is a form of emergency contraception that must be started within 72 hours of having unprotected sex.
Bro 1: That slut I banged last month skipped her period.
Bro 2: That's not cool.
Bro 1: No worries, she took the month after pill. Problem solved.
Bro 2: Well played.
The pain reliever you take the morning after an all-night alcohol binge (aka tylenol, advil, excedrin, etc.) to relieve the pain of previously stated binge