Learn English – Meaning of “sup the homeslice? harvard jv field hockey is da bomb…”

What does full bloody mean in full bloody Italian?

I'm not sure of the intent, but possibly the word is used as an intensifier or mild expletive in the phrase. I imagine the word chosen would be different if it were the FFI. :)

Should blooded be used instead of bloody, in this case?

If it were meant as an intensifier (bloody Italians!), no.

Would full blooded Italian be understood as who completely has Italian blood?

Yes. Full-blooded Italian would mean someone whose ancestry is completely Italian — or at least someone who is steeped in and fully exhibits the Italian culture.

The character Joey is attempting, with no success, to appear a specific age, and thus also appear privy to idiomatic language specific to the youth of that age at the specific time in which the situation is set: that is, in the vernacular common in 1998-2000, when Joey was 31, not the vernacular common in 1989, when Joey was 19.

Were he depicting the slang common in the US at the time of his youth, he would be saying "Dude, f$%k dude, bro, major uncool" or something similar.

The comedic aspect is the combination of the juxtaposition of his clear actual age and his attempt to appear younger, and his concomitant utter failure to capture the tone, style and tenor of the vernacular speech common at that time for that age and cultural cohort.