Flying Ryanair (Allegiant/Frontier/Spirit of Europe). Just my buddy and I on a three seat row. Buddy sees an open row across the way and jumps over there. Russian guy sees that and asks the flight attendant if he can move up a row, with me. Immediate stench. Just as you describe. If I hadn’t been up the previous 25+ hours, it would have been a lot worse.
Funny, because stereotypical almost middle-aged Russian dude. Husky, a bit overweight, and track suit.
Maybe he was aware, because he bought some cologne from the inflight magazine.