A "v-string" is typically a type of underwear that is characterized by a narrow strip of fabric that runs down the back, forming a V-shape. There are several different synonyms for this type of underwear, including G-string, thong, and T-back. These terms all refer to similar types of undergarments that are designed to minimize panty lines and leave as little fabric as possible between the buttocks. While these styles are often considered to be quite sexy and alluring, they can also be quite uncomfortable for some people, particularly if the fit is not quite right. Overall, though, they remain a popular choice for those looking to spice up their underwear collection.