I do think that Shane gets a Russian language tutor. He sees that Ilya is always having to think, speak, and translate in his second language. And he knows that Ilya is fluent by this point, but if he's serious about forever with Ilya (which he is) he wants Ilya to be able to communicate with his boyfriend in his native language. He also saw how much his grandparents struggled with learning English as adults and how much more expressive and talkative they were when they spoke Japanese at home together.
So he gets a tutor. He meticulously researches her (she's from Moscow, so he'll learn from someone with Ilya's same accent). She's signed to more NDAs than he can count. She has 10 years of experience, she's certified to teach English and Russian, and she has 4.8 stars on MyTutor.
Shane pays her a frankly concerning amount of money to make house calls. Twice weekly, unless he's on the road, she arrives at his apartment to teach him foundational Russian. She gives him workbooks, Russia cartoon recommendation, podcasts for beginners, etc. He tells her he's learning because his boyfriend is Russian and she outlines a course that focuses on domestic language first (as opposed to travel or business). She even teaches him what she calls a 'culture course' with lessons on Russian music, food, and various traditions.
She's only a few years older than Shane and he actually finds himself looking forward to her visits. At this point, she's the only person other than his parents that knows he has a boyfriend.
About 4 months in, Shane finally feels comfortable enough to ask about what he'd been very excited about learning.
"You want me to teach you how to talk dirty to your boyfriend?" Ekaterina raised an eyebrow.
"Um," Shane blushed. Was this a little too far? Was this inappropriate to ask of a tutor? "Yes? If - If that's okay, I mean."
A slow smirk spread over her face. "This will be fun. Fun for me, now. Fun for you, later."
"I made a list," Shane admitted. He wasn't going to back out now, he put a lot of thought into his list. He turned to it in his Russian notebook and handed it to her.
She scanned over it indifferently. "You will use all this in one night?"
"Yeah, probably. Is it too much?"
"It is good you have a Russian man," Ekaterina said. "They have good stamina. Mostly, anyway."
And while it was a little embarrassing for Ekaterina to correct his pronunciation of please let me suck your cock, it helped that she seemed just as comfortable with that as there is tea on the stove.
Though, maybe he shouldn't have learned those phrases at the same time, because Ilya will never, for as long as they live, allow him to forget asking, while down on his knees and with excellent pronunciation, please let me suck your tea.