Prefacing that it wouldn’t even be for my own pleasure- sexual pleasure, that is. Sadistic masochism would be the driving force behind the deed (explained below).
I have a theory that Jack loves it when Tammy and her massive caboose make on-screen appearances, and wants to showcase it (since he doesn’t edit it out like a modesty-conscious Christian would [lol he’s just lazy]). He secretly wants people seeing her dump truck, because it’s one of the only things at this point that he can pridefully hold over the haters. It’s almost as if to say “lookat that shit, guiyz. I pulled that in. That’s what I get to enjoy. It’s MINE. That’s right, losers…I *FUCK*.” Never mind that the Jack-Tammy origin story isn’t remotely like that- Jack wasn’t a macho man with incredible rizz, but some fat, schlubby zero whom she settled for. Still, Jack probably feels a sense of quasi-misogynistic ownership over that ass, and likes people knowing it.
My only goal would be to sully that aforementioned sense of ownership. What you do is show up to the barn and make her feel as if she was 21 again. Take her on a prolonged trip to a land of sexual delights that most women dare not dream of. Make her cum twice with your mouth before she even gets to see your dick. Make a new woman out of her- she goes into that bedroom sounding like Lucille Ball in the 1950s, and comes out sounding like Lauren Bacall in the 2000s. It should be an almost life-changing degree of pleasure experienced by her.
It is imperative that Jack and the public knows that this happened. Whether Jack learns through hearing her wails and moans from the other side of the house, or from proof of the dirty deed making its way onto a New Zealand bird-focused forum, it is required that he find out not just about the sex, but the public knowledge of the act as well. It would take away one of the last things that he takes pride in: exclusive bragging rights over the poop deck on the S.S. Tammy. It would probably devastate him more than losing the function of his left arm.