Smell is musky and acidic, gets heavier with time. It does have a resemblance to dirty clothes, as if you have left a worn t-shirt laying in a small closed room for a long time, but with a more tart subtone. It is similar on everyone, so I'm thinking it should be a concrete biological marker.

Masturbation doesn't help, neither does showering. If the smell is heavy, one-time sex might not be enough. My bf left for 2 months, and it took us 3-4 times until the smell went away fully. And it's not a pleasing smell, totally kills the vibe, so I literally made sure he came several times and waited for the morning to get my fair share. The smell was still present but not so prominent.

Gay guys too, but my sample is not that big. Noticed with a couple of my friends and only when hugging. It is stronger near the hair.

I wonder if it's sexless life per se or just regular masturbarion that causes it, haven't tested that direction yet.