A Dress is a body cover — it covers your breasts, your vagina, and your anus. This example shows a dress that is quite a bit longer than necessary to provide full coverage.
Although it may seem to be an advantage that the dress is so long and modest, and it is certainly in keeping with the spirit of the Dress Code, in practice such a dress can be a disadvantage. The reason is that an Inspector can’t see by just looking at it whether the dress is hiding an infraction, so a girl wearing this dress is more likely to be inspected than one whose pussy is less completely covered.
A convenient feature of this dress is the front zipper, which allows a girl to get more comfortable. She can unzip it a little bit to show cleavage, if she likes. Or she can unzip it all the way, but leave her breasts covered, as illustrated above. Since her breasts remain covered, there is no need to zip it back up — As you can see, she is quite modest even with her dress unzipped.
Then, if she wants to take the twins out for some fresh air, she can simply unwrap them, and let them bask in the sunshine.