Monster Girl Love 3: The Other Woman

Oscar is a mad scientist. A particularly careful and lucid one, but since he has been tinkering with a dimensional travel device that fits around one's waist, he is nonetheless probably mad. He successfully transports himself to another world, much like his own, only to find certain strange changes in the women there, including his finacee's alternate self. He returns home, only to find the change spreading rapidly... Starting with his own fiancee.

A brief list of scenes and fetishes follows.

Scene 1: In which a madman tries dangerous equipment on himself, and suffers the consequences. Fetishes include public sex, coitus, amazonian monster girls, and exceptionally warm bodies.
Scene 2: In which the fuckmonster plague is explained. Fetishes include sexual exhaustion, muscle-control orgasms, coitus, and amazonian monster girls.
Scene 3: In which our hero returns in triumph. Fetishes include coitus, and maledom.
Scene 4: In which our hero inflames the passions of his fianc©e, and loses a very nice pillow for it. Fetishes include fingering, both anal and vaginal, brief orgasm denial, and firebreathing.
Scene 5: In which our hero's fianc©e pays the price for her lover's indiscretions. Fetishes include transformation, oral sex, and overpowering.
Scene 6: In which life returns to normal, more or less. Fetishes include jealousy-induced coitus.