While being tickled is to many people a very unpleasant experience and was even used as corporal punishment by the ancient Romans, people with this fetish find it extremely sexually arousing.
Tickling Fetish is also known as Knismolagnia. The Greek word “Knismos” means Tickle and “Lagnia” is Greek for Lust.
This “Tickle Game” is often combined with Podiaphilia (the fetish for feet) when that body part is a particular tickling interest. This is called Podiaphillic Knismo.
The tickling is most frequently done by using fingers, various objects like feathers (Pteronphilia), by using the tongue to lick a person but there are even people who use insects!
There are Tickle Dating Apps where fetishists find like minded Titilagnia (Knismolagnia) lovers.