Depending on the stimulation programs you choose, you’re likely to feel a tingling or tickling sensation caused by simulation current which is generally inevitable. On a good side, you will get used to it pretty quickly and it’s highly unlikely that those sensations will be causing any discomfort or pain.
Powerdot is designed to allow you to precisely adjust the intensity of contractions for most comfort and all sessions always start at the lowest intensity, which majority of users will be unlikely to feel.
Do keep in mind that, for performance training, the best effect from stimulation is established at the maximum tolerable levels.
The rule of the thumb is that you should never experience any pain or serious discomfort during your stimulation – if you do, then you should consider reducing the intensity straight away.