Maybe she can phase the entire amniotic sac out the body then hold the placenta like a balloon, in case of Zero wants to do it rough and doesn't want to bump the baby. And she won't have the physical discomfort since the baby is outside. Her sprite will change back to the normal one but with the baby balloon. If she got jealous of other girls baby bump then she might ''borrow'' the baby for a day (still connecting with the real mother ofc).
FFS, this is a straight up body horror flix especially with the Rogue baby hoarding idea.
In a middle of the night, you heard someone knocks at your door. Each knocks keep getting harder and louder. You opened to find Rogue's standing in front of you. She's smiling, her grin is uncanny wide and her dark circled eyes implied the craving. But you can feel it, it's not the usual craving. And why does her stomach is bloating with multiple bumps. You have to ask her but she simply said ''All of your seeds belongs to me, me only''.
That was a nightmare to picture. I need to sleep this one off.