Houraisan KaguyaOpen up! It's an express delivery! The girlfriend you ordered is here...
Express delivery here as a meme is actually a hoax since there are cases where the police in China use phrases like this in order to lower the guard of the person in question and get them to open the door. The more common term is "we are here to read your water meter", and this phrase has since became a euphemism for "having trouble with the law", albeit usually in a comedic sense.
As for the girlfriend part...surely you all can tell, right?