Actually, Red Eva, BDSM stands for Bondage, Discipline, Sadism & Masochism. Believe me! D&S or Domination and Submission came a lot later.

Early bdsm writing focused a lot on discipline, but tickling was certainly a popular element. Tickling a helpless women is certainly a kind of torture.

The discipline part of B&D (Bondage & Discipline) became known as flagellation, but it was also known as CP (Corporal Punishment). This was a big sector of the publications market. Snuff literature was categorised as 'Hard Flag' or Hard Flagellation, and included torture, mostly Mf.

CP involved spanking, also punishment with the kinds of implement that were used on schoolchildren in Victorian times, such as the cane, the tawse and many other implements still used in B&D today. Mainly on the bottom, but also on the soles of the feet (podiatric stimulation). There were (and still are) a lot of photos of reddened bottoms. Riding whips are used a lot in pony girl scenarios.

There were adult magazines specialising in tickling.