When a fat nasty person eats food and gets shit all over their face, but they don't notice it and they just keep eating their food while you can't help but stare and vomit.
While Rachel was eating her sub a little mayonnaise dribbled down her face, but she didn't notice. Sean could only sit and stare in disgust and complete nausea as she kept chumming on her sub.
A dating tactic involving the use of one's good looks to lure a less attractive mate into a one-sided and emotionally unsatisfying relationship.
(Taken from the crab fishing term for illegally using perforated dog food cans to bait a trap)
"Damn, she's so fine! She says she likes me too."
"No man, she's way out of your league. She's just chumming."