(one) last fling
A last experience of doing something impulsive and enjoyable before one is no longer able to do it. We decided to go for one last fling in downtown Tokyo before flying back home in the morning. I know you're eager for a last fling with your friends, but there's too much work to get done before you move out.
last fling
A final enjoyment of freedom. For example, He's planning to have one last fling before joining the army. This expression employs fling in the sense of "a brief period of indulging one's impulses," a usage dating from the first half of the 1800s.