When printing things “in the air” we have to create provisional supports (that we’ll remove after the printing is done) in order to avoid the drop of the plastic.
What slicing software are you using? I think every of them have an option like “add support” or something like this. For example, Cura has the support options at the Basic Menu.
I suggest you to read something about supports in 3D printing, this article of 3DHubs explains it so well 🙂
Hope it helps 😉