http://www.getchu.com/soft.phtml?id=776282
http://vndb.org/v12809

http://www.dlsite.com/ecchi-eng/work/=/product_id/RE118317.html

Bitch x Imouto
Ecchi little sister's veil of seduction enshrouds all!

The Miyamas were a happy household of five.
Eldest brother Kei, after his father's remarriage,
had adjusted to life with a new stepmother and two young stepsisters.

One day having lost his keys, Kei sneaked into the back door of the house
and spotted Shiho stealing his underwear.

He was like a deer in the headlights, but she was unflinching:
"I want sperm," she said.

Shiho moved on her big brother with purpose.
He couldn't resist. After they had sex,
he was forever caught in her web of seduction.

Can Kei keep his head on straight from now on!?

* Sperm hungry imouto expands her menu: reverse r*ping guys she's just met!

* Life after sexual surrender! Will her temptations exhaust his spirit?

* Ecchi imouto's unbelievable activities...
Buzzing between her legs while she walks around town, soapland part-time work,
masturbation in the park... even making a home-made dildo!?

Base +11

Worth noting that the title of the game is actually "Yarimanko". 娘 is supposed to be read as "ko", not "musume", and it's a play on words, "yariman" basically meaning slut and "manko" being vagina.

Base +10, MonsterDarling +9, SirIndigo +7

(18禁ゲームCG) [130726] [softhouse-seal] ヤリまん娘 ～俺の妹はビチビチビッチ～

Base +7

So one sister is already a town bicycle?

Base +6

@byran47
kinda,she's just a blowjob slut.she only fucks the brother.

Base +6