I recently noticed the tags tanga and tanga panties, and I had no idea what they meant. Wiktionary for tanga defers to tanga briefs, which are defined as "A form of revealing underwear with front and rear panels connected by a narrow band or string around the hips." Isn't that synonymous with string panties and/or fundoshi? They are being applied to some posts which are not string panties like post #9034356.
Further investigation has shown that tanga is a very old tag, dating to 2012, but has only been applied a total of 17 times.
tanga panties however, seems to be a month old and almost entirely the work of a single user. In fact this is just one of a whole host of hyper-specific tags this user is also propagating, which includes string bikini panties (topic #31142), ass cleavage, natural wedgie, exposed gusset, panties_around_thighs, picot trim panties, picking wedgie, panty spread and panty roll. None of these have wikis except the first, which says to not use the tag.