Aya Ikeuchi from the Ping Pong/Eroge hybrid 温泉DE卓球 from Studio b-Room. This game has very few CG, so I'm surprised it worked at all!

Aya is kinda like a female antagonist according to VNDB, she's your lesbian rival out to earn the affections of the girl you've been pursuing before you do!

Appearance: red hair, red eyes,

Outfits: Kimono, underwear