To acquire ownership of something, usually incarnate, by forcefully pushing said object into ones vagina (or anus) then subsequently pushing it out in an act of "birth." This is commonly done, but not limited to, aesthetically pleasing children that you wish to make yours.
"Oh Alex!!" Laura said with utmost excitement, "Isn't baby Benji larsman S00 cute! I will make him my own flesh and blood by reverse birthing him!"