Tenshi no Secret Service

Minako, who works at St. Benedict Hospital, is ordered by the head of the medical department to provide a special service in a locked room. It is part of a training course for special female nurses and is a special service for wealthy patients hospitalized at the hospital. Hitoshi, one of the patients who has become successful at a young age, discovers her weakness while receiving Minako's service during her training and launches a counterattack. Minako writhes in agony as her erogenous zones, which she herself did not know she had, are attacked. And then... the angel in white transforms into a lewd and seductive woman... [Translated from Getchu]