I think it would be cool if, when you escape with the "Heavy Balls" upgrade, instead of letting you go because she wants the chase to go on longer, you escape because you came so much it overloaded her system temporarily, stunning her. Since that's your goal with the machines, I think it would make sense.
Also, being able to upgrade semen volume (How much you cum per ejaculation) would be hot as fuck. Not sure what sort of gameplay purpose it would have though, maybe making disabling traps more consistent and making it work from longer ranges?