Training shots
According to an investigative reports from around the time they were first approved for use by firearms officers in the UK, the Taser shots used on police and others in training are usually at a considerably lower voltage/power than in regular service use against civilians. (This might be because TASER International wants to reduce the risk of catastrophically bad publicity in the event that someone is killed by a Taser during training; the company pushes its products using the "non-lethal" claims, but has had a reputation for being ... less than straightforward when it comes to the question of safety and the risk of fatalities). Unpleasant as they no doubt are, low-power training shots may give a misleading impression as to how bad it really feels in active use.