The proper way of wearing a fundoshi, rokushaku style, is illustrated in detail in this interesting illustration. The results of botched tying are visible on the bottom left, with the correct tie visible at the bottom.
You can see other styles of fundoshi, though merely modelled by loli, in the article on the subject.
Artist ヰンジ / Yinji, presumably a lady, has some superb homoerotic illustrations to her credit, visible below:
“Hi no Maru Fundoshi.”
More fundoshi, though sported by females, in the gallery on the subject.