'ras zobbi' is a Maltese derogatory term that can be doubly translated in English as meaning either 'dickhead' or, more literally, 'the tip / (head) of my dick'. It is somewhat more of an insult than its English counterpart may signify, often used to describe people that are either being utter pricks or are acting in a manner that makes you want to bash their skull in.
Giving a couple of practical examples (because why wouldn't I), it usually goes something like this:
Maltese: Kif hadt ras alla teqred bro, qazziztli ras zobbi
English: You've done God's head in with all your whining mate, you made my dick tip feel nauseated.
Maltese: Ara ras zobbi, ha joqghod gej bil-liba wara li qalaghli ghoxx kemm ghandi biex ghamilli pjecir
English: Look at this dickhead, now he's gonna conjure up shit after I let him bend me sideways in return for a favour