IBP - Ghost Lover
Kif and Marg encounter an alien similar to the preying mantis of earth, except it is a male. Marg suffers the effects of the encounter, but Kif is overwhelmed by it, and escapes sickbay to return to her lover to willingly let him complete the mating ritual.
Find it at erotickynk.com under IBP. As usual, the public get still shots and Patrons enjoy the full animations and juicy - very juicy - sound files.