B(ondage) D(iscipline) S(adism) M(asochism)
Hows does tickling fit in there?
Oh let us count the ways.
Tickling is a most effective form of Discipline. In face for many S&M practitioners it's a bit too much. I've known bonded slaves that could take a cane whipping that would leave them bloody, safe word out in the face of tickling. In the toolbox of training, punishment, and general amusement, tickling is a highly effective tool.
Sadism. In the hands of a Sadist, tickling can be a brutal experience. A Sadist enjoys inflicting a form of suffering on their subjects. Employed correctly it is a tool that a sadist can deploy to great effect.
Masochism. There is no suffering like that of a lee being tickled. Many love it in that special way that Masochists enjoy suffering.
Tickling is a tool that fits in many areas of the BDSM experience in many ways.
Most tickling fetishists have a connection to the S/M part of the equation. The OP mentions provoking begging. This is Power exchange. an aspect of one person forcing control over another. A partner enjoying taking that power thru causing a form of suffering (pleasurable though it might be) and another partner having their control taken away, and enjoying the experience of struggling to hold it as long as they can, before they surrender.
S&M are just two more names that designate points on the power spectrum between partners. They are rolls (or aspects if one prefers) of people in sexual play with each other, where not only the physical, but mental and emotional aspects are active. Remember that Ler and lee are our fetishes specific analogs to Top and bottom, Dom and sub, etc. Once one remembers that the place of tickling in BDSM is not hard to find.
Myriads