From past experience force feeding is stressful for both you and your dragon and really should be a last option.
If your dragon is still eating I would dunk a worm or two into the olive oil or applesauce. They get plenty into their system that way and you avoid the trauma and struggle.
If you decide you really do need to syringe I wouldnt recommend trying to wedge the syringe in because you can bruise and cut their gums very easily if they wriggle or try to flick you away (mine bloody do!). Insted I found it is much better to put your thumb and first finger together on the tip of their nose/mouth, then slide your fingers apart and down the side of your dragons mouth for about 3 cms and then gentley apply pressure.
He should open his mouth a crack and when he does pop the syringe tip in and slide it down the side of one side of his mouth. If you squirt in right at the top they can aspirate the liquid.
If he wriggles and you are having a hard time because he's trying to back away I used to simply put him onto a hand towel and fold it back onto him, not a full burrito but it means he cant wiggle backwards.
Best of luck.
Forever slave to my rescued monsters:
Billy (now sleeping)
Ruben (now sleeping)
Dex (now sleeping)