How to create a perfect edge? I want to create a bottle of shampoo, but I encounter some difficulty...








When I apply subdivision surface I got this mesh, how can I fix this?

Here is my blend object:
https://drive.google.com/open?id=177eO74yxTY8biekbXR2gIK2Fk5QB16HN
As this hole is supposed to help to open the bottle, I suppose you've made a mistake and that the topology is rather something like that (I've separated the plug to make it more understandable):