One summer day Takumi Saiki (protag/teacher) was checking the empty school when he found a forgotten bag.
Inside it was Sayaka Natsuyama's dirty gym clothes. She was a student of his.
Takumi had often thought about Sayaka in a sexual way, and in a moment of weakness...
Just then, Sayaka walked in and saw him.
He apologized profusely to the lolita, to which she replied:
"Take off all your clothes, Mr. Saiki, and stand there. Put your hand on your thing."
That was the first of many days that Sayaka made Takumi cum...

[From DLsite English]