"Shore Leave" is a silly, breezy episode, but honestly the funniest thing about it is the sheer amount of effort that goes into getting Kirk consensually laid.
The whole fanon thing about him being super horny after however much time in deep space and eager to go on shore leave is ... let's say, not much in evidence. It takes the combined efforts of so many people to make this happen, and he doesn't even have a fling with a real person, she's more of a glorified blow-up doll. But she has to be a specific glorified blow-up doll or he won't do it, it turns out. Like, I would never have guessed that the "getting Kirk laid" subplot of the famous shore leave episode would feel so much like some very concerned zookeepers trying to get a cheetah to fuck.
The context of the episode is that he's so intensely stressed as the episode opens that he's screwed up his back, isn't sleeping right, and his reactions and attention and reading rate and everything are all slowed from just the level of tension he's carting around. Airing order makes this, uh, extremely credible: the three preceding episodes are, in order, "The Menagerie" (parts 1 and 2), "The Conscience of the King," and "Balance of Terror."
So he's not dealing well, McCoy is badgering him about not taking care of himself medically, Kirk's yeoman (Tonia Barrows) has a crush on McCoy and is reiterating his concerns about Kirk's health on the bridge, and Spock is scheming about it too. They get to an appropriate planet for shore leave, which everyone pretty desperately needs except Spock (according to Spock :P). But Kirk refuses to take even a few days off work despite ALL of this, so Spock ends up having to use McCoy's medical log of... everything wrong with Kirk and Spock's own talent for emotional manipulation to trick Kirk into agreeing to take shore leave.
To very concisely summarize a very wacky premise, the shore leave planet's residents are basically running a super-advanced, personally tailored ... carnival, of sorts, for all their guests, based on what they telepathically pick up from said guests' minds: they manufacture lifelike, but not actually living, facsimiles of whatever they desire in that moment.
This still isn't sex for Kirk, btw. It's beating the shit out of this 20-year-old asshole upperclassman at Starfleet Academy who had relentlessly bullied the 18-year-old Jim Kirk, then a grim, rule-abiding first-year cadet (yes, this is the episode that establishes that Kirk was bullied five years after surviving a genocide for the crime of not being fun to be around).
But Kirk doesn't just want to kick this guy's ass, he wants to do it in a fair and square fight where his victory feels earned and justified, because nerdy straitlaced teenage Jim is just never buried that far below the surface of glamorous 33-year-old Captain Kirk. Seeing Finnegan (the bully he hated but never fought in reality) does remind him, however, of the other main figure in his life back then: his girlfriend Ruth.
We don't know how long he and Ruth dated, only that the last time he saw either Finnegan or Ruth was 15 years earlier and neither looks any older than then; Ruth definitely behaves and looks like she was a bit older than 18-year-old Kirk, more sophisticated, and frankly less troubled than him (even her costuming has this vibe), so she may have simply graduated or moved on in some other way. There's no grudge implied; it feels more like this older, elegant, very mild-mannered girlfriend from back then was his first serious love and there's always going to be a part of him a little bit in love with her (he hasn't seen her since he was 18; we don't know when he actually met her, fell for her, or when they got together, only that they definitely were together that year). At any rate, he's just happy but puzzled to see her exactly as he remembers her.
A bunch of plot things happen, they all discover that this is basically one big, super advanced fairground. McCoy checks out the underground facilities the people in charge have and is allowed to essentially just order whatever facsimiles he wants rather than getting random thoughts in his head projected out. McCoy being McCoy, he orders some chorus girl replicas and takes them to the surface, even though he was basically mid-romance with Tonia Barrows. Barrows is understandably pissed about the chorus girls—it's turned out the replicas aren't actual people, more like very lifelike dolls, but still.
McCoy has the brain cells to stick with Barrows instead of the chorus girl replicas, who (hilariously) take Spock's arm; in classic gay Spock fashion, he extricates himself with obvious horror and hastily announces he's going back to the ship. Kirk also isn't interested in the chorus girls, and is starting to fight about how he should be the one who gets to go back to the Enterprise when he sees the Ruth replica again, and he decides, at last, to stay and relive his teenage romance for a couple of days of shore leave.
Kirk has a good time with "Ruth" and goes back to his job on the Enterprise at the same time as everyone else, but holy shit, this took the combined effects of Spock smuggling Pike to the Talosians and Kirk having to condemn him to death in a court martial; Kirk facing Kodos the Executioner after 20 years and figuring out the genocide-apologist serial killings of Lenore Karidian while father and daughter repeatedly suggest he's subhuman; Kirk leading an incredibly tense standoff with the Romulans (and the racists on his own crew) that prevented the outbreak of another war but resulted tragically in the Romulans' suicides; Yeoman Barrows (with whom Kirk has an entirely platonic relationship, on both sides) prodding Kirk about his health; McCoy's badgering and dutiful medical notes on Kirk's sky-high tension; Spock's use of all of the above and immaculate emotional manipulation to get Kirk off the ship at all; the aliens who run the telepathy shore leave wish-fulfillment workshop providing replicas of Finnegan and Ruth; and the Ruth replica herself (but not any of the other sexy ladies). Damn.
I guess I can't complain about Yardstick's dental too much. At least his jaw is in one piece, unlike Finnegan's.
Finnegan seems to be in pretty good shape aside from that jaw thing. His joints are in surprisingly good condition and he appears to have no problems jumping. His tail is very stiff, which is part of Osteochondrodysplasia.
Honestly, wish I had this comic, from the snippets I've seen! Give me 25 pages of prissy, uptight academy-era Kirk getting bullied by friends and foes alike! Peak fanfiction!