Well the Seductive Trait and Comeliness can stack, giving you a total of +4 (Also I will require you to have Comeliness for it, as that would only make sense, either Comeliness or a really high Charisma, like Charisma 8 or something)

It would work like this (it will be a little different from other Addiction Flaws since it is a very... unique addiction). +2 XP you need to satisfy your urges once a week or get -1 to Charisma. +3 XP you must satisfy your urges once a week or be at a -1 to both Charisma and Willpower. (normally the XP is less and for the higher bonus its once every few days, but since this addiction is very... unique... I am just making it once a week). 

You wouldn't have to eat a whole person either just a bit of flesh to satisfy your cravings for it. (like a chunk or so). But yea, if you were seen by other people doing this, then you would probably get killed or something since they would consider you an abhorrent freak.