The actual F-word can only be heard in films. If you watch Miss Baek, for example, it’s everywhere. Also in Kondo: Rise of the Rampant, in Fasten Your Seatbelt. All the time!
In dramas, they just say Aish! where the sh probably stands for the begining of shipbal, which is the corresponding F-word.
Here is the relevant part (I blurred it for sensitive souls):
■■/씨팔 ssibal (prn.shi-bal) Used as ‘■■■■!’ ‘■■■■■■■’ or ‘■■■■■■!’ “Derived from씹하나[ssib hada], the verb ‘to ■■■■’.
Sometimes written as an acronym asㅅㅂorㅆㅂ(SB), similar to the Chinese SB.
Can also be written ’18’ which has a near-identical pronunciation in Sino-Korean numbers (십팔, shib-pal).”
씨발놈아! Shi-bal-nom-a! You ■■■■■■■■■■■■!"
씨방 Shi-bang Like ship pal comes from ‘Ship-pal’, which means, “to sell the ■■■■■”, or “to sex with ■■■■■■■ ‘Ship-pal’ is also used instead of ‘Shi-bal’.
씨팔 F***
씹 Ssib (prn. ship) ■■■■, sex . Can also mean the female reproductive organ.
■■■ shib-seh-ggi ■■■■■■■ ■■■■■■■ (also piece of ■■■■, ■■■■■, ■■■■■■)
씹하다 ssip ha-da to ■■■■ (verb)
아, ■■… Ah, Shi-bal… Ah, ■■■■…"
You may want to consult this document I compiled on Korean swearwords and slang.