LORELAI: OK, I need more tulle here. I need the feeling of a major tutu, OK?
A tutu is a traditional ballet dress, often made from tulle, which is a fabric made from lightweight fine netting.
Amy Sherman-Palladino herself was a ballet dancer, and had the chance to turn professional. She became a writer instead, but there are numerous references to ballet in Gilmore Girls, and her show Bunheads was based around the world of ballet.