What a G string is and where the name comes from
Short answer: A G string has a narrow strip at the back instead of a back panel. The name comes from the term gee string, used for a narrow band around the hip.
How it is cut
At the front there is an ordinary small panel. At the back there is only a cord or a narrow strip. That makes it the cut that shows least under close fitting clothes. See bamboo briefs.
Why it is worn
Under tight trousers and thin dresses the only way to avoid a visible edge is to remove the edge. That is the whole reason the cut exists.
Comfort is personal
Some do not feel it, others cannot stand it. That cannot be decided in advance, and it depends more on body shape than on brand.
The material in the gusset
Whatever the cut, the gusset is the part that matters for comfort. A gusset in cotton or viscose moves moisture away from the skin all day. The measurements for the different cuts are in guide to briefs and underwear. See bamboo underwear for women.
Frequently asked questions
Where does the name G string come from?
It comes from the older term gee string, used for a narrow band worn around the hip.
Why do people wear a G string?
Because it does not form a visible edge under tight trousers or thin dresses.
Is a G string uncomfortable?
That is very personal. Some do not feel it, others cannot use the cut.