If you haven't already downloaded the latest patch, you might need it, it fixes an h-attack for the rubber lover. The only instance that I can recall is that it happens when battling the hypnotist and rubber lover duo. You need to be equipped with a rubber suit first, which you can get from the "crossdressing rubber magic" pleasure attack from the rubber lover, then undergo the "oppai sling" pleasure attack to get them inserted. If your "fake augmented breast" status reaches 9 stacks while wearing the rubber suit, the breasts will become permanent even when the suit is removed. The more your breasts are teased, the quicker they'll become permanent. There might be another way to get them on the creation route, but other than that, I think you only get them in bad ends.