Yarn is slang for "interesting narrative or tale", and as @MothaFuckinTreeStars correctly pointed out, bant is "banter".  You're not slow, I had no fucking clue what this lard barge was referring to either so I googled it. What a catch! Ghetto hoodrat with three metastasized cumshots, (no doubt belonging to three different one night stands that came to their senses) who wants to sit on her ever expanding ass while her and her brood leech off you. It's so pathetic it's comical really, she wants so much but brings absolutely nothing to the table, well except for her low sexual market value and a few bags of Doritos. I don't get why men aren't jumping at the chance to be with this delightfully elegant cheesehog.  Last sentence was satire, obviously.