If you don't want any explicit content then you should refrain from looking for yaoi, what you're looking for is shonen-ai. There is a big difference.
Anime -
Monochrome Factor
Yami no Matsuei
Princess Princess
Gravitation
Antique Bakery
Angel's Feather
Uraboku
Gakuen Heaven
Loveless
Sukisho
Junjou Romantica (whether you would class this as explicit depends on your definition, there is no sex shown but it is strongly implied that is what is going on)
Sekaiichi Hatsukoi (same as above)
Manga -
Seven Days
Only The Ring Finger Knows
Cafe Latte Rhapsody
Gorgeous Carat
Self Portrait
Loveholic
Yellow
Anime -
Monochrome Factor
Yami no Matsuei
Princess Princess
Gravitation
Antique Bakery
Angel's Feather
Uraboku
Gakuen Heaven
Loveless
Sukisho
Junjou Romantica (whether you would class this as explicit depends on your definition, there is no sex shown but it is strongly implied that is what is going on)
Sekaiichi Hatsukoi (same as above)
Manga -
Seven Days
Only The Ring Finger Knows
Cafe Latte Rhapsody
Gorgeous Carat
Self Portrait
Loveholic
Yellow