Need help with a movie ID based on description

[Ziggy Plock]

I remember a scene from a Soviet or Russian film, but I forgot its title. A young girl of OT age 14-16, who studies either violin or piano, has a secret plan to seduce some man. They end up hiding the salami (as in: really doing it) in classic her-back-to-the-wall position, but all of a sudden, she freezes up, cause she thinks she can hears a person walking. Her lover asks "for certain?" so she says , so course I'm certain, because, I've got perfect pitched ears (=to hear musically, when a musician can spot a false note, an out of pitch sound 100% of the time)

Can anyone identify this movie?