This phrase is used to refer to the act of trying to steal someone's boyfriend or girlfriend. It's a metaphoric expression which literally means 'sawing the floor', implying the action of pulling the ground from under someone.
Examples
- Spanish: Ella está tratando de aserruchar el piso a su mejor amiga saliendo con su ex novio.
- English: She is trying to 'saw the floor' from her best friend by going out with her ex-boyfriend.