Mpreg Central

https://youtu.be/y4BwGMzphA0

I don't think it's technically mpreg. at least I don't think. But has great belly expansion scenes.

Honestly fascinating.

Woah! That's an excellent find and well worth watching!

Now, that's the sort of belly I'd like to grow - minus the bomb inside, of course! 

Some decent dialogue during the birthday scene too.