The two types of tickling were named by psychologists G. Stanley Hall and Arthur Allin in 1897. Knismesis is reminiscent of a feather trailing across your skin, or perhaps a bug walking on you. It’s also the type of tickling that you can perform on yourself. Gargalesis, on the other hand, is more aggressive and can cause breathless laughter. It tends to target specific areas of the body where we are sensitive to tickling: underarms, waists, ribs, feet, and necks.