Where do you get laundry additive?

I don't really think it attracts vampires, but it might have been fun, heh. I haven't paid that much attention to the additive effects but I gather it's basically "good smell for floral stuff, bad smell for food stuff." In fact I want to say that adding the plasma fruit didn't have any effect at all, but I'd have to go back and look. It just caught my eye because it was available to use. Actually having different effects seems like too much granularity to hope for.