There can be a high injecting testerone (steroids) though some steroids are pills.
Injectable steroids stay in your system longer so they need to be done usually once a week while pills might be take every day (this varys to the type of pill)
The high (rush/rage) from take any form of testorine can vary from different people. Most people are filled with energy that rushes through whole body. Pure rush. They think they can do anything/go on for hours on end. This can lead to Rage, b/c steroids can raise your aggression. Some people tend to lose control of themselves (roid rage).
The usage of steroids brings with it added side effects depending on the type used.
Can hinder your sex drive
Gynaecomastea (bitch tit)
water retention
acne
hair loss
blood pressure increase
enlarged prostate
jaundice
though some of these occur with extended usage of steroids, some of these side effects may be brough about by one use (gyno-bitch tit: You get this from using steroids that aromatise into oestrogen in your body, or by using HCG or Aldactone. Once you have it the only cure is surgery. also high blood pressure, roid rage, loss of sex drive, and water retention can all occur after one usage)
some steroids only cause small to no side effects, and for the ones that do, other drugs are used to prevent some side effects.
so if your looking for the energy rush that lasts for days on end, and don't care about the side effects then go ahead.