Yaoi is Boy+Boy Love and Yuri is Girl+Girl Love.
Sometimes it involves hentai.
To avoid hentai, go for Shonen-Ai which is for Yaoi couples and Shoujo-Ai which is for Yuri couples.
Example with Naruto:
Yaoi: Naruto and
Yuri: Sakura and Ino
Yaoi is for girls and Yuri is for boys. :)
SakuIno is a beautiful Yuri! :)
Yaoi and Yuri is awesome!