Wait, jack also using Lando at breakfast?? How could he even get hard, oh my god, how much of puppy Lando did he witness beforehand, did he train him too? It seemed like he was there when Lando got his collar?
okay, so! as far as i could tell from run boy run, oscar's prey were almost all going to be absolute freaks anyway. lando didn't go onto the island blind, he knew oscar was into plenty of pain play and didn't much care if lando wanted it or not (even though he always did). so i decided that i was going with a similar assumption for jack, meaning that when he actually felt relatively safer and somewhat less out of his mind with exhaustion/fear/what have you, he would absolutely find lando irresistibly hot!
and i couldn't say exactly how much of the puppy play he'd seen, but he's definitely seen lando fall into subspace a LOT! in my mind there's definitely been scenarios where oscar's domming jack and also letting him play with lando, who would be so entirely out of it! and yeah, maybe he did get to train lando a bit! he's constantly in awe of how easily lando obeys oscar, until that's actively lessening their chances of staying alive (i like to think that even though he knew from very early on in hunting season that lando wasn't going to try to escape, he still didn't want to leave lando in an unsafe situation).
the collar's a slightly different story. i think oscar put it on the first time when they were alone, but then it started to become a thing they could incorporate with their victims! change the story around a little, maybe even pretend that it is the first time lando's being collared. with jack, i picture it as them being together somewhere or other and oscar brings out the collar, but there's a lot of do you deserve it/you have to earn it first dialogue in there, which is what jack sees! at the time it would have been unbearably hot, in hindsight and knowing that lando knew who oscar was, fairly disturbing. that's also the fun part of jack getting some extra time compared to other victims—so much more time for him to stew over everything!