LORELAI: If you cut him [Richard] a little slack, I’ll wear my Porn Star tee-shirt to dinner next week.
Presumably a tee-shirt which has “Porn Star” written on the front. Such tee-shirts are still common, and it is hard to say what Lorelai’s might look like. We never see it, and it seems unlikely she would wear it to dinner with her parents.
The Annotated Gilmore Girls 