With the syringe (minus needle of course!), u just drop a bit on the beardies nose, just above the mouth, & smear a little of this to both sides of the mouth area without being invasive.
It may take seconds or minutes, so patience is a virtue, but as soon as they lick their nose, which they invariably do, it's a matter of holding the syringe & sqeezing it so the food flows slowly but consistently, which they then keep licking.
It's not about shoving it down their throat, but being gentle & patient so their appetite is stimulated over 2-3 days & they start feeding on their own again.
Always offer live food first before syringe feeding, & if they don't eat any or as much as you'd like, then go the syringe feeding.
Sugar free apple or chicken baby food is a winner, & vets have the A/D canine/feline cans of food that u just add water to (preferable not much & warm) to make it easier to syringe feed.
Syringe feeding reptiles I've found can get very messy, so a rag to wipe your beardies mouth at the end is recommended.
Hope this helps, & clarifies the meaning of syringe feeding of Beardies