Swing Out Sisters (2014)

Two sisters fight for the affection of their younger brother, and eventually decide to share him. Both of them are considered to have high quality animation for hentai.  

Both feature two sisters fighting over who gets the affection of their little brother. In both, one of the sisters is strong-willed and a bit tomboyish, while the other is mild-mannered with nadeshiko qualities. Swing Out Sisters focuses solely on the protagonist's relationship with his two sisters, while Tayu Tayu (which still focuses primarily on the siblings) is a harem.  

Both stories are about incest and how both of the brothers try to make their sisters happy. 

Both OVAs involve sexual relationships between siblings, three exactly, two big sisters and one brother in both cases, with lots lovey-dovey greatness in both. 

Two sisters involve their brother in incest relationships 

First Love is 3 Episode OVA with 3 Different Story & 3 Different Couples If you like love between siblings, I recommend you to just watch the first episode of First Love which focus to love story between kasumi & her brother  

Both hentai about older & younger sister having sex with their little brother 

Renketsu Houshiki is 3 episode OVA with 3 Different story & 3 Different genre If you only like incest route, then you just only need to watch episode 1 

Similarity : Having sex with older sisters Different : Yuuta only have 2 sisters, both is biological sisters Kuuya have 6 sister from different mother 

Similarity : Having sex with older sisters Different : Yuuta Sisters is actually a biological sister (Swing Out ​​Sister) Sosuke Sisters is only a half-sister (Gakuen Shimai)  

Similarity : Both tell the story about having sex with older sister Different : Ryouichi Fujisaki is much more evil rather than Yutta. I will not tell you why because it can be said as spoiler. 

Similarity : Both hentai tell story about love & sex between sibling Different : - In haramix MC must making sex with his sister because that was the only way to save his live from death - In Swing Out Sisters, MC making sex with his sister just because "love"