I believe I have the answer to why Cantonese called male masturbation as "Ta Fei Kei(TFK)" which means beating the aeroplane in English. The word TFK started in the 90's in HK and KL if I'm not mistaken. During that time, video games arcade in shopping mall are very popular among youngsters, and there was this fighter jet arcade game which uses joystick to control the jet.

One fine day, Ah Beng and Ah Seng went to shopping mall video games arcade to play that fighter jet game. While the two were enjoying the games to the max, being young, curious and dirty minded, suddently Ah Beng say:

Ah Beng: Seng arr, dont you think this joystick we are holding resemble our kuku jiao?
Ah Seng: Yahor, as if when I'm jerking off.
Ah Beng: Exactly dude, my kuku look exactly the same as this joystick.
Ah Seng: LOL, your imagination are good.
Ah Beng: Yeah dude, from today's onward we will call masturbation as TFK.
Ah Seng: Cool bro, TFK la lei!

The word spread very quickly among Ah Beng and Ah Seng friends and friend of friends. Everybody seems to agree with Ah Beng theory and therefore, the word TFK officially means male masturbation in Cantonese speaking community.