My girlfriend, who was so convulsed that she couldn't pull my penis out, had sex with me all day long. (Kawakami Nanami, DVAJ-370)

He developed feelings for a female friend who already had a boyfriend and arranged to have sex with her. However, her vagina gripped his penis tightly, making it impossible to pull out, so he had to endure the ordeal like that. Even the slightest movement between them caused intense friction...