I had to think of a way to attach the head to its body now. Again, it was quite the struggle to find a suitable idea mostly I wanted to keep the half sphere design I made of the head. 

At the end of the day, I came up with the idea of using the "Thread" function (filletage) to attach the head to the main body. Basically, the head would be the equivalent of a bottle cap. 

In order to do so, I had to design to cylinder that would be the body and the bottle cap together, which I did by following this video : 

The particularity of this tutorial is that it doesn't use the fillet function but rather the spire function around. 

It eventually came out like this :