BBSW: Big Breasts, Small Waist is a web published roleplaying game focused on sexual situations and activities. The system is point based and similar to both GURPS and BESM: Big Eyes, Small Mouth, but uses only d10s for task resolution. Each character has three attributes, Body, Looks, and Talk. Abilities may be purchased to flesh out the character (also similar to GURPS and BESM) by taking disadvantages to gain points to spend. Social interaction, combat and intercourse yield "Sexperience" points which can be spent to increase attributes or skills. There are also rules for various sorts of erotic equipment.
Three settings were originally presented. Hentai Earth, Fairy Land, and Hell.
The game has been circulated in (at least) two versions -- 0.5 (2011), credited to Zaratustra, and 1.0 (2001), credited to B.B. The 1.0 version has expanded lists and a concise introduction to basic roleplaying concepts, but is essentially unchanged. How the 1.0 version was released ten years before the 0.5 version is unexplained. There is also another version credited to Zaratustra released in 2001, further confusing issues.