A slang term for an obeese woman's breats. They tend to be deformed, covered in stretchmarks, and bulging out of a shirt that is too tight. People with lardsacks tend to think they are very attractive and try too pull off a get-up that is not even appropriate for those of supermodel status.
Origin: A nasty girl who OVER exposes her breasts to attract attention to them and divert everybody's eyes from her poor excuse for a body.
You: Jesus! Look at her, she should not be wearing that. Nobody wants to see that.
Friend: Ew. Those lardsacks need to be covered up.
You: Yeah! She even wore shorts too!
Friend: Lord have mercy on us
(Then somebody usually proceeds to gag)