After a moment, Jeff turns back to her little brother. "Hey, Max... I know you don't want to go to bed right now, but, considering how interested you are in it... How would you feel sleeping, with Alice, in the place babies are made?"
Max looked up, a look on his face that can only be explained as excitement as he thought about it. "Y..Yes! I would love to see..." Jeff smiled, as she sat down on the floor. "Well... Only girls have it, so previously you'd have needed to do it with Alice, but... Now I'm a girl, and can let you see it for yourself."
Max was excited, seeing the place he came from. Jeff took off her pants. "I'll let you know now, this one hasn't had any, but you can still see inside." With her lower clothes off, she grabbed Max and pulled him in. "But, I do have a few rules while you're in there..."
"And they are..?" Jeff smiled, before continuing. "One, you need to share the space with Alice. Two, don't fight in there. Three... Keep your diapers on, unless I say you can take them off... And, when she wakes up, tell these to Alice as well."
Max quickly agreed. "Okay!" And so, Jeff was ready... Almost. "Alright. But, before you go in, let me go get Alice situated." Jeff reaches into Max's diaper, accidentally brushing against her little brother's genitals, and pulls the naked Alice out.
Holding Alice closely, Jeff heads to Alice's room, Max excitedly following close behind. Setting the girl on the ground, she grabs a diaper, and quickly puts it on her. "Alright."
Sitting down, Jeff aligns Alice's head with her vulva. She spreads it apart, and pushes the girl inside, moaning a bit, with Max watching. Once about half of Alice was in, Jeff spoke again. "Alright, Max. You ready?" Max nodded.
Jeff grabbed Max, pulling him closer, before pushing Alice in further. With Alice now having just her diaper and legs sticking out, Jeff pushed her little brother's face into her sister's diaper, pressing against it to send both in at once. This whole time, Jeff was moaning in pleasure, Alice's legs locking around Max's head.
Jeff pushes more, Max's diapered butt going in as Alice is entering the cervix. She pushes in as far as she can, with Alice fully inside the womb as she can no longer reach Max. "Alright, Max. You're basically there, but I can't push you the rest of the way in... You need to crawl on your own."
Max crawls the rest of the way in, Jeff still moaning as her brother finishes the final stretch. She pulls her pants back on, before laying down on Alice's bed, exhausted. "That... That was actually amazing." She puts her hand on her belly, feeling the two twins within... Max gets himself comfortable, his legs wrapping around Alice as he lies on top of her sleeping body.