Hello. What really helped my pacing for tickling scenes was embracing a really sloppy first draft, followed by one or two heavy rewrites. I'll write the tickling scene vaguely; go over the position the lee is in, where the tickles happen, how the ler is tickling them, and any lines that pop into my head.
Then I’ll reexamine the scene and try to get into the character’s head.
How is the lee feeling? Are they feeling anything other than ticklish? Are they scared, aroused, nervous, or embarrassed? How do they react to the touches? Are they trashing their bodies with all their strength to get away? Are they trembling and flinching at the touches? Are they enjoying it and leaning into the touches?
Same for the ler’s side, with an extra bit of what is their motivation? Are they tickling the lee because they’re being blackmailed to? Or is it revenge, a punishment, or sex? Does tickling the lee make them feel powerful, horny, conflicted, or guilty? How does the ler feel about the lee’s reactions? Are they enjoying every flinch and cackle. Do they keep their touches light to watch the lee squirm, or dig their fingers in so hard that it almost hurts the lee because they want to force the laughter out?
Having this in mind, even without going into detail helps out my tickle scenes immensely. In the Goater Ghost, which I have posted here, the lee Norma is an unwilling victim that gets trapped. The ler, the ghost of Mrs Goater wants revenge on trespassers. Even though I don’t go much into how Mrs Goater feels about Norma’s reactions, it gave me space to put in a little monologue of Mrs Goater’s past that gave weight to her motivations while also giving a space for the tension to grow as Norma came to realize that Mrs Goater wasn’t going to let her go unscathed.
Focusing on the how and the why can really add length and depth to a tickling scene without focusing on how the fingers are digging into the armpits or scraping down soles. You don’t need to spell everything out bluntly either. Your readers are smart, trust them to connect the dots on their own.
As for a satisfying ending, a goal should be accomplished by the end of the story. It doesn’t need to be a strong or complex one. It could be as simple as ‘the lee escaped’ or ‘the ler has gotten off.’ Give a few lines on what the character feels and what might come next. Is the lee relieved and trying to forget? Go one step further and have them get an email with a link to a video of their tickling to give the story a chance for a sequel? Or end it there with the lee worried about what the ler might do with the video. Does the ler let his captive go, satisfied? Or do they want more and start planning their next victim, or maybe decide to keep their first victim? Was the scene between two lovers cuddled up in the afterglow? Maybe the lee is planning to be the ler next time and wants some playful revenge for what the ler just did to them.
None of this is gospel, and simply what has helped me take my writing to the next level. I hope this helps you. Good luck.