Are they sharing an enclosure ? They may look very cute together but beardies . even as hatchlings are NOT social beings when it comes to other beardies , there will always be a dominant who will get the lion's share of the food and the best basking and sleeping spot and will grow faster, and the "pal" will loose out and fail to thrive and will be continuously under great stress and will often be bullied too.
If so - they ARE NOT PLAYING - this is dominance behaviour and can quickly escalate to biting and vicious attacks (beardies are fully capable of killing each other) --- SEPARATE THEM IMMEDIATELY and KEEP them SEPARATED .
It is very unwize to let two beardies be out together too (unless M and F and it's a brief romantic encounter).