I hold her just behind her head so I can keep her head from moving and am able to move it the way I need to. I then have the syringe in my other hand and gently push up her lip and aim the tip of the syringe into her mouth and down. It's kind of hard to explain, but just do what feels right to you and practice will help you refine you technique and before you know it, it's a piece of cake for both of you!

Good luck!