You've probably heard of Albert Einstein's theory of relativity. Or if you haven't heard of it but have seen movies like Christopher Nolan's 'Interstellar', you'll know what I'm talking about: spacetime and gravitational time dilation. Meaning, different observers see events and the passage of time differently. (The scene in which Cooper and Brand return to the spacecraft from the ocean planet is one of the scariest in the entire movie, in my humble opinion.)
However, Einstein's theory requires that the two observers have different velocities or are in different places with respect to a gravitational field. And I'm here to tell you something remarkable.
You don't have to be in outer space to affect the behaviour of time. You can control time here, on Earth, relative to yourself instead of another observer.
What I mean to say is that time is an emotion, and you can make the decision as to whether is passes quickly or slowly. But not with respect to others, but with respect to how quickly or slowly you're used to experience time passing.
You may have already noticed this by sitting in traffic. Since you're not going anywhere, time seems to go by like a slug. And if you're having fun and enjoying yourself, time seems to run away like Usain Bolt. But you hardly ever have control over the "speed" of time in situations like this. (You could have taken another route, though. But a traffic jam is not always forseeable.)
No, I mean real and noticeable control of time that is inferential from the example above but differs in nature dramatically. Here's how to do it.
A) To increase the speed of time, sleep a lot, see your best friends, watch an entertaining movie, or do other things you find extremely enjoyable.
B) To slow time down, make your life as hard as you can: go running multiple times a day, do plank exercises, take up a monotonous job for 12 hours a day. Hang from a bar for two minutes. Stare at a wall for an hour with earmuffs on.
You're sure to notice the change in the perceived speed of time, at least with option B.
Doing enough of hard activities every day you can make one month last forever.