Once you enter Jibral Castle, you will find out that the kingdom is being besieged by the same purple smoke that hit your character's village. You will be recruited to help and during the night, Nene's ship appears. Gorgo soldiers are there as well with massive harpoon guns. They fire into the hull of the ship and you assist with reeling it in.
The achievement is based on your reaction time and ability to hit the appropriate buttons. Unlike some of the other achievements of this type, this event will require three different buttons to be pushed. My combination was Y,B,X but yours may differ.
1) Make sure you are watching the screen and not just blindly assuming its the A button like the other achievements.
2) While others have pitched the rounded lighter technique, what I do is set the controller on my lap and use both my index and middle finger to tzap repeatedly downward. It has worked so far for me.
3) Be prepared. I was taken off-guard when this came up as the ordering on the TA page makes you believe this doesn't appear until later in the game.
4) Save before you enter the castle! There is a save point in the castle's courtyard. Save it and then head in so you can easily reload if you mess things up.
I hope that helps! Enjoy your 5G once you pop it!