noun, noun or participle which takes 'suru'
long phone call; being on the phone for a long time
Refers to a telephone conversation that lasts a long time, often with a nuance of excess or inconvenience. Commonly used with する to mean 'to have a long phone call'.
彼女と長電話してしまった。
I ended up having a long phone call with my girlfriend.
長電話は料金が高くなるから気
Be careful, because long phone calls get expensive.