Playing a Schubert piano duet by the end of their first meeting, their fingers flutter, their hands graze and they throw their heads back in ecstasy.
Later, just in case you failed to notice that headboard-banging musical encounter between Lee Seon Jae, a delivery boy and YouTube-taught piano prodigy, and Oh Hye Won, an arts administrator old enough to be his mother, he recounts it in lyrical, sexual terms to an online confidant.
It is an odd instance of overstatement in Secret Love Affair, a South Korean drama which often stays cool.
Emotions are abundant in this current hit show by cable channel JTBC but mostly contained and submerged in art, which is how it should be, as Hye Won (Kim Hee Ae) advises Seon Jae (Yoo Ah In) before a performance.
Hye Won, the wife of an insecure piano professor, Kang Joon Hyung (Park Hyun Kwon), meets Seon Jae after her husband, trusting her ear for talent more than his own, arranges for the young man to play for her in the couple's home.
The Kangs soon take Seon Jae under their wing. The husband hopes to take credit for his latest student's career someday, unaware that he has been the third wheel since the day his wife gave the lad an audition.
Seon Jae regards Hye Won, not her husband, as his teacher because she is the first person who really responded to his music and recognised his musicianship.
He also has such an instant rapport with her - the intimacy between a pianist who shyly reveals his musical thinking and a rapt listener who misses not one note - that actual, non-instrumental sex, when these two have it, seems to be a mere formality.
Much of Secret Love Affair's charm is how boldly it deviates from other adultery dramas (such as A Good Wife last year) where a woman has to choose between two men.
Early on, it is obvious that Hye Won's marriage is a strategic alliance to secure her job in an arts foundation, her husband's career at an affiliated music college and their lifestyle.
Still, she laughs when Seon Jae declares: "You just need to love me. You have nothing to lose. It's obvious I'm the one who loves you more."
You laugh, too, because he is so wrong yet so right.
She does have things to lose, starting with her stable, comfortable life. But when they are in his attic, which is covered in egg cartons as cheap soundproofing, she is much happier there, listening to him and his music, than in her tasteful home.
For her, the choice is between what is real (her lifestyle and her career) and what is true (art and love).
The show makes no bones about which side it is on, however. In its book, love is what makes art beautiful and imprints urgent feelings - Seon Jae's longing for Hye Won - on old songs.
3 Days has the rippling body of a mindless thriller, but the soul of a poet.
After been-there-done-that K-dramas from Iris (2009) to City Hunter (2011), it is unlikely that 3 Days will quicken your pulse, even after it puts a president (Son Hyun Joo) and regional peace in peril.