The original word 'Friggin' is a rude term for a female masturbating. People have formed completely wrong definitions of the word over time and people aren't 100% sure of what it means.
Some people use 'Friggin' as a way of expressing their anger/shock/surprise e.g Friggin hell
boy 1: my girlfriend was friggin herself in front of me last night
boy 2: she masturbated in front of you?
boy 1: yeah, all night