Lady in a White Coat: Lewd from the Front and Back (1997)

Hiromi Katori, a new employee, felt unwell during work and went to the infirmary. Then, instead of the usual Maki Kitagawa, the person there was Hanako Minamida, a flashy middle-aged stranger. Hanako tells her girlfriend Katori that the nervousness of her trying to force herself to apply to the company is causing her to lose her mental and physical balance. While telling him that she doesn't have to be useful to the company and that she should not lose her individuality, Hanako gently places him on the bed and takes her dick in her mouth.