Ilya buys Shane a bottle of cologne during the situationship era. He doesn't admit that, of course. He would never admit to how long he spent spritzing scent strips, the long conversation he had with the sales associate about top notes, heart notes, and base notes, the amount of money he spent on that one bottle. He tells Shane it was part of some endorsement he did but that he thinks the scent doesn't really fit him; that it would work better on Shane. He convinces Shane to let him try it on him and the open desire, the hunger in Rozanov's eyes makes the world feel like it's tilted ever so slightly on its axis, like Shane's balance is a little bit off. He fucks him with an animalistic sense of urgency, nose buried in the crook of Shane's neck when he comes, teeth clamping down on the muscle of Shane's shoulder. Honestly, Shane is pretty sure he would have heard about any cologne brand deals Rozanov has but decides not to question it; he accepts the bottle anyway. He starts wearing it every day and the thrill of secretly wearing Rozanov's mark on him while going about his everyday life is nearly overwhelming. It feels like ownership and Shane doesn't know what to do with how much he loves that. Every time he meets up with Rozanov, he can see the exact moment he smells it on him and delights in how it drives him wild every time.
He starts rationing it more carefully when he sees the contents of the bottle dwindling. He dreads the day he will find it empty. Sure, he could buy another bottle but it wouldn't feel the same. It would feel like a poor imitation of the mark he's been proudly wearing in secret, right under everyone's noses.
The first time he meets up with Rozanov without wearing it, the reception is cold. He can feel the anger simmering under every word. He doesn't address it until he's pushed Shane to his absolute limits and it comes out in mean and harsh and accusatory comments that try to cover up how affected he is by Shane not wearing it; the worries about what it means that he's stopped. Shane is far enough gone by then that he admits he's been saving it; that he's close to running out. It comes out in oversensitive whimpers and half-swallowed whines as Rozanov's punishing thrusts punch the pathetic confession out of him. They don't discuss it further but, after that, Rozanov starts gifting him colognes with increased frequency.
By the time they're in a relationship, Shane has a whole shelf in his bathroom dedicated to his extensive collection. Whenever they go anywhere, Ilya will select a scent for Shane to wear. He will lovingly spritz him with it, breathing him in before they leave, and Shane preens under the attention. He can see it in Ilya's eyes, every time he catches a whiff of it, he can feel it in the way his arm tightens around Shane's waist. The quiet mark of ownership that lingers on Shane's skin without anyone else knowing that he bears Ilya's brand at his pulse points.