Although they might seem like they get along, one might be intimidated to enter a hide like you saw there. By the way, did you quarantine the new gecko for at least 90 days before introducing it? The new gecko could harbor all type of bacteria that could harm your gecko.
"
Tail Wiggling
There are a few different tail wiggles/shakes that leopard geckos will use:
Slow Tail Shakes – When a leopard gecko shakes their tail slowly, they are telling other geckos that they are there and are aware of their presence. Normally the gecko will lower themselves to the ground and will shake their tail slowly. Sometimes this can also be a sign that the leopard gecko is excited.
Fast Tail Shakes – Male leopard geckos will usually shake their tails rapid if they are put in the same presence as female leopard geckos. This tells the females that there is now a male in the area and that he is aware of the females being there.
Defensive Tail Shakes – Leopard geckos will drop their tails if they are ever threatened so the prey will go after their tail instead of the gecko. As you can imagine, leopard geckos will shake their tail to divert attention whenever they feel threatened. Generally the gecko will lower their body to the ground and will point their tail up slowly wiggling it. They will often have their head arched up staring at the threat.
Leopard geckos may also use a defensive tail shake if they are unsure about another gecko. If your gecko is making this gesture when you are near him/her, do not try to pick them up because they may try to bite you. Instead you should let the gecko know that you are not a threat. You can try standing there until the gecko relaxes or you can slowly place your hand into the tank, away from the gecko so he/she can investigate it or hide. Eventually your gecko will become used to your presence.
Excitement Shakes – You will usually see this type of tale shake when the gecko is hunting bugs/eating. Usually it is more common in younger geckos, but adult geckos will do it every now and then. When this occurs the gecko will raise their tail and slowly move it from side to side, and then when they are about to attack the insect they will quickly shake their tail before attacking. " (
Leopard Gecko Behavior & Body Language)
