Skirt

A skirt is a garment that resembles the lower half of a dress and is above the knee. Many girls like to flash what's under their skirts. Schoolgirls are required by law to wear skirts.

Miniskirt
Miniskirts are skirts that are shorter than regular skirts. Well, skirts at least go below the buttocks, but miniskirts very rarely go that low. It is illegal for a miniskirt to be greater than 7.5 inches long.

Zettai Ryouiki
Zettai Ryouiki (Japanese for "Absolute Territory") is a grade of how sexy a skirt/dress/dress-length-shirt and stocking/sock combo is by measuring how much bare thigh skin is between the skirt/dress/dress-length-shirt and stockings/socks. Sometimes, shorts are used instead of skirts/dresses/dress-length-shirts.

These are all the grades, F to S:
 * F: The socks only go up to the ankle. 0% sexy. BOO!
 * E: The socks have the same length as crew socks. 12% sexy. Little better.
 * D: The socks go up 3/4 of the way to the knee. 25% sexy. Hmm...
 * C: The socks go up all the way to the knee. 50% sexy. Wow!''
 * B: The socks go up over the knee. 63% sexy.
 * A: The socks are very high. 100% sexy!  *fap fap fap* 
 * S: The socks almost go up (or completely go up) into the skirt/dress/dress-length-shirt/shorts. OMG 1000% SEXY WOW!!!!!!!!!!!!!  *fapping intensifies* 

Advantages to Wearing a Skirt

 * People can see your panties. Unless you're not wearing any panties. Then they saw your pussy. Unless you happen to be a Scottish man. Then the person looking up your skirt just saw a penis that isn't his or hers (yes, hers). And unless they're gay or a straight girl, they're disgusted by it.
 * You can masturbate without much issue.
 * The person looking up your skirt can pull your panties down (again, unless you're a Scottish man) and start licking your pussy or start sucking your she-penis (if you're a shemale).
 * And that's it!