DASS-054 She got the pleasure of having the back of her throat attacked, and was having deep throat sex hidden from me. - Yui Tenma

Toshio's girlfriend Yui visits Toshio's house. - Toshio's older brother Hikaru meets Yui and finds out that she is a masochist. - Hikaru, who planned to train Yui, looks at Yui and treats her kindly. - One day, when Toshio was away, Yui came to the house to retrieve something he had left behind, and she received tea from Hikaru and spilled it on Hikaru's crotch.