Why does she use "for" after "on"?
Native speaker’s answer
Rebecca
"Holding on for dear life" is a common phrase that is used in English. It means to cling to something very tightly, usually in extreme circumstances. Sia uses "for" after "on" because the phrase would be grammatically incorrect and would not make sense in English. Using "for" gives the reader/listener an indication that the person is holding on to something for a specific reason.