Knismesis and gargalesis are the scientific terms, originally coined in 1897 by psychologists G. Stanley Hall and Arthur Allin used to describe the two types of tickling. Knismesis refers to the light, feather-like type of tickling. This type of tickling generally does not induce laughter and is often accompanied by an itching sensation. Gargalesis refers to harder, laughter-inducing tickling, and involves the repeated application of high pressure to sensitive areas.
While the two terms are used in academic papers, they do not appear in many dictionaries and their origin is rarely declared. The term knismesis comes from the Ancient Greek κνισμός (knismós) meaning 'itching.’ The term gargalesis stems from the Ancient Greek γαργαλίζω (gargalízō) meaning 'to tickle.’ The suffix -esis is used to form nouns of action or process.
You may wonder why this term appears in the BDSM alphabet, but as I discuss in all of my presentations, BDSM is not always a sexual practice. Especially in the context of S&M framework, these practices utilize sensate practice to elicit sensory reactions that will produce a chemical response in the body.
These chemical charges (dopamine, epinephrine, norepinephrine, and to a lesser degree, testosterone and oxytocin) in specialized parts of the brain (the parietal operculum, ventral striatum, the primary and secondary somatosensory cortex, the anterior insula, anterior midcingulate cortex, and sensorimotor cortex and the left frontal cortex) create a super sexy cocktail of happiness. In some practitioners, tickling (knismolagnia) can be just the right kind of touch to elicit an orgasm.
In fact, a recent study (find the vid and journal article) showed that Most of the respondents said they found tickling sexually gratifying, and around a quarter said they had achieved orgasm just through tickling.
Over 20 percent reported they had enjoyed tickling sessions for over an hour at a time. The data also identified two distinct roles in sexual interactions involving tickling: the tickler and the ticklee.
There were some consistent themes around which parts of the body ticklers and ticklees like to focus on – feet featured heavily, unsurprisingly – but there was also some variation depending on the nature of the tickling being discussed.
Here's something they didn't tell you in school: Knismesis was favored around regions like the ears, neck, and back, whereas gargalesis was generally preferred on the torso and armpits.
The data also provided some insight into why some people love being tickled or doing the tickling, with responses including enjoying the feeling of submissive, or taking pleasure in the ticklee’s physical reaction.
Another interesting finding that emerged was the role of childhood experiences in the development of a tickling fetish, with several respondents saying that depictions of tickling in cartoons they’d watched as a kid triggered their continuing interest in the practice in adulthood.
As the authors say, “Tickling is an intimate activity that requires a certain level of mutual trust. It can bond individuals and serve as an outlet for sexual energy. Future studies should therefore investigate the mechanisms by which tickling triggers sexual pleasure.”
Really, all of this to say, "No, cumming from being tickled isn't weird. and you're not the only one, and, yes, they definitely make tools and toys for this which you can find below (of course)."
And check here and here for more info!