It’s considered a polite gesture to knock softly before entering a room. We usually refer to this action as “ton ton”.
“Ton ton” is the movement of someone lightly tiptoeing up the stairs, or softly tapping the shoulder of the person beside them to catch their attention.
It’s also used to talk about situations that happen smoothly without stopping.
For instance, “ton ton” is when you meet someone you’re interested in, begin a steady relationship, and then eventually marry the love of your life without facing any hiccups – as if it were naturally pre-arranged by fate.
Conversely, “don don” is reserved for big, pronounced movements.
Like when a debt collector bangs loudly on the door at ungodly times of the day, or back when your mother would unceremoniously stomp all around the room in an effort to try and wake you up for school.
And last but not least, we also use “don don” when making great progress in a short amount of time.