I don't want to be a debbie-downer here, but are you actually a lee, Wade? And if not, and she is legitimately torturing you despite your pleas for her to stop, it raises questions around consent tbh.
Please tell me if I have this wrong.
That's a legit question. And the answer's encased in the tangled thickets of my personal psychology -- as it collides with the even more impenetrable recesses of Sarah's psychology -- so I don't know if there's an answer that will make sense to other people. Not sure if there's an answer that makes sense to me. But fair warning, this response is probably going to run long as I try to figure it out here...
I'm genuinely very ticklish, so being tickled relentlessly -- especially by someone with an edge of sadism like Sarah -- is an intolerable experience. And yet I'm on this site reliving the experiences of being tickled by people by retelling them here, so clearly it's not straight-up trauma for me. My unruly brain derives satisfaction not from the sensation of tickling itself but rather from the experience of not being able to stand it -- and from the existence of other people who want to subject me to something I can't stand. So I'm oscillating between the suffering experience of being too ticklish to handle this, and an enjoyment of having been forced to experience that suffering. Typically the actual experience of being tickled relentlessly is something I'm desperate to escape when I'm in the moment, but then when it's over I can -- almost intellectually -- appreciate the agreeable elements of having been forced to endure that.
As for Sarah, her choice to tickle me seems to be largely opportunistic -- she knows I'm susceptible to it, so it's a convenient and entertaining way to torment me in revenge for the ways I've harassed and annoyed her in the past (and the present). I've said that if I weren't ticklish, or if there were an easier way to pester me, Sarah would go after me another way. But I'm not 100% sure about that -- there really isn't any other means of tormenting someone like tickling, with its useful combination of playfulness, intolerability, entertainment value, humiliation, and social acceptability. It's so playful and harmless and mundane a form of torture, after all, that Sarah can even enlist my wife or my sister-in-law or other people (who ostensibly like me a lot more than Sarah does) in menacing me and they'll join in without any pangs of compassion. So it's her uniquely good fortune that my weakness involves tickling, because some other form of punishment probably wouldn't be an option. Maybe some kind of teasing or verbal abuse -- though Lord knows we both engage in those kinds of things anyway -- but even those tactics can be more problematic socially than tickling.
I've also remarked in the past that if Sarah had any inkling that there was any minuscule aspect of tickling that was pleasant -- or even less than 100% torturous -- to me, she'd abandon it in a heartbeat, because for her that would ruin the punishment value of tickling me. But even that dynamic is complicated. Like everyone else in my life who tickles me or has tickled me -- my wife, my sister-in-law, exes, friends, coworkers -- I'm sure Sarah is responding on some level to the fact that my response communicates a sense that the experience of being tickled isn't genuinely harrowing for me. There's something about the way I bounce back afterwards that communicates that doing this kind of thing is ultimately fine, even though I was sincrerly pleading for it to stop only minutes before. As one of my coworkers once exulted after she tickled me for the first (and not the last) time: "You're not mad!" If I emerged from the experience of being tickled in tears, or furious, or shouting "I never want to see you again," even the heartless Sarah would feel compelled to give up her sadistic little hobby. She's twisted, but she's not a sociopath. But I don't do that -- even though it would solve some of my problems, free me from suffering at Sarah's whims, and reconfigure our power dynamic to my advantage -- because I don't feel that. Sarah, like other people in my life, senses from my responses to her vicious little stimuli that this is a safe practice.
So everything about the quirky and contradictory elements of ticklishness -- at least as I experience it -- combines into a narrow band of social and individual permissibility that makes tickling me mercilessly the ideal way for Sarah to take out her frustrations on me. It is indeed 100% non-consensual in every accepted sense of that term -- I don't explicitly invite or condone it, I try to escape and avoid it, and when I plead for it to stop I mean it -- and from my end it's frequently excruciating and puts me in a position of utter helplessness that's unfortunate from both a practical and a psychological standpoint. But both society's perception of tickling and my own complicated responses to it place the act in a zone of acceptability which gives Sarah one perfect weapon she can deploy against me at will.
Told ya I'm a tangled thicket.