Studio was CLOCKUP, so those animes with the nearest relationship should be Requiem (Anal Sanctuary) by Milky and Dyogrammaton by Discovery.
Looking at the style however it could be Taimanin Asagi (Pixy) and the Yakin Byoutou OVA [Nanase Ren (training Ren), Yagami Yuu and Kasama Mana] by Soft on Demand.
All these titles are licensed or AniAn property (DLsite) though, so they may not be posted on A-O.