Onna no Ana

Onna no Ana (literally, Girl's Hole) is a collection of short stories about boys and girls linked by strange connections at a certain school.

1. Onna no Ana, (Girl's Hole)
   
2. Onna no Atama, (Girl's Head)
   
3. Onna no Buta, (Girl's Pig)
   
4. Onna no Oni, (Girl's Beast)
   

(Source: Anime News Network)