I've been giving Desmond medication and critical care daily for 6 weeks now. I've gotten pretty good at it
I'm right-handed, so change this around if you are not. I like to sit on the floor with my right leg higher than the left and then I stand Desmond on them, so that he is fairly upright. Then, I put my hand around his head, with my thumb on the fat stores on top and my pointer finger comes around to pull down his lip. I pull down his lip and put the tip of the syringe in and then gently move it toward the front of his mouth. He usually opens his mouth as I move toward the front but if I reach the front and he hasn't, I just slowly go back and forth. Once he opens, I squirt the medicine in - I go quickly if it is just .1 or .2 mL, but if it is more, I do a little at a time to be cautious. He will move his head around once he opens his mouth, so I have to be quick to depress the plunger. I took some pictures to show my process. The last picture shows where he usually opens his mouth from moving the syringe along his lips.
I just got some syringe nipples from Beautiful Dragons Rescue that have made it much, much easier to feed the critical care. But the method I described above, I've been using all this time and still am for the meds. I'm not sure about choking or aspirating - I just try not to squirt it into the back of his mouth.
Good luck!