Considering you mixed in brainwashing, and considering she’s mechanical looking, you could do some brain sex theme’d stuff. Data corruption. Virus injections. Scenarios that increase in the sexual degree at which certain themes plays out, such as foreplay that eventually hits sex and then has a creampie like finish is also a good idea. Then if the creampie finish leads to something such as egg laying, cuminflation, change of personality that leads into a more sexually aggressive person, etc. If only temporary. For example: You could create entire escape sections where the protagonist needs to escape from within their own mind from the corruption, or the womb, while the physical body is doing something else, something lewd. Depending on the narrative of the storyline, you could surround an entire theme around a certain corruption taking place in the body and just expand that out sexually speaking into gameplay segments.
What’s important is that you don’t limit your imagination, only throttle it, slowly pushing down on the gas pedal so to speak over time.