Cameltoe
Fanart with the cameltoe tag is ecchi and fanservice. You can see a woman's body through tight swimwear, leotards, athletic leggings, or tight pants. This wardrobe malfunction would be embarrassing in real life, but anime character designers and fan art intentionally make it bigger to add softcore sex appeal.
The Japanese term for tight clothing is kuikomi (食い込み), meaning "biting into" or "digging into." Fanservice-dependent genres like sports anime, magical girl shows, and sci-fi shows with tight pilot suits (like Evangelion plugsuits) repeatedly use this visual trope. The ecchi genre teases viewers with suggestive content without explicit pornography. Clothing can make a character look hotter and more vulnerable.
The wallpapers in this tag are provocative. Much swimsuit and gym uniform (buruma) art highlights fabric tension to highlight curves. To emphasize the anatomical outline, artists use this tag with dynamic poses like characters bending, stretching, or being seen from low angles. If you want art with detailed anatomy and subtly suggestive fanservice, this tag is perfect.