Stimulation can be described as an increase in a person's physical energy levels and are beneficial when it comes to feelings of wakefulness, movement, performing tasks, talkativeness, and general exercise.   
At lower levels, stimulation typically presents itself as encouraged more so than forced. This can be described as feeling distinctly energetic, but in a purely controllable fashion that does not overwhelm the person with involuntary movements should they choose to stop expending large amounts of energy. It is often accompanied by other coinciding effects, such as motivation enhancement, analysis enhancement, thought acceleration, focus enhancement, and appetite suppression, which can result in a distinct increase in the person's overall productivity.
At higher levels, stimulation typically presents itself as forced more so than encouraged. This can be described as the effects of increased energy becoming so pronounced that the person will be incapable of relaxing and feel an irresistible urge to perform some sort of physical task. It is often accompanied by other coinciding effects such as thought disorganization, focus suppression, short-term memory suppression, increased heart rate, teeth grinding, temporary erectile dysfunction, sweating, and dehydration, which can lead to a distinct decrease in the person's overall productivity.
Stimulation is most commonly induced under the influence of moderate dosages of stimulant compounds, particularly dopaminergic stimulants such as amphetamine, methylphenidate, MDMA, and cocaine. However, it may also occur under the influence of other compounds such as certain psychedelics and dissociatives.
- Stimulation (PsychologyDictionary) | https://psychologydictionary.org/stimulation/
- Stimulation definition | https://www.merriam-webster.com/dictionary/stimulate
- Chapter 2—How Stimulants Affect the Brain and Behavior (Treatment for Stimulant Use Disorders) | https://www.ncbi.nlm.nih.gov/books/NBK64328/