In this clip, poor little Tonya is restrained in stocks, where all the toes of her ticklish feet are tied. Her hands are tied behind her head and her armpits are getting wet in anticipation of the upcoming action...
Katrina and Alevtina are in good mood, they literally pounced on bare feet of defenseless Tonya and on her vulnerable armpits.

Tonya does not know where to go, she yells, begs to stop, and gasps from tickling. Alevtina and Katrina are so cruel, how it turned out during the session.
The ticklers distributed the ticklee's body in this way: while one tickles her bare legs with all possible devices, the second torments the upper body and armpits. From time to time the girlfriends-ticklers change places.

Tonya will remember this session for a long time. She was tickled to hysterics and was already ready to explode and destroy her girlfriends :-)
After the shooting, Tonya came back from tickling for another half an hour, she was just lying down and sighing heavily. Her tormentors, looking at her, felt awkward, approached and apologized, trying to make amends.
This is what hypersensitivity means.