Glider Questions,
There is an easy solution to this
stop putting your hands in the cage. No more biting.
Other than putting food in the cage each night, which is usually done prior to the gliders waking up, and resetting toys or cleaning, there is no reason to put your hands in there. That is their home, their first safe place, and you are intruding on their safe place. At least until you have built a little better of a friendship and bond with them.
Do your hands smell like food? Our hands usually smell like food especially if we've just given them a treat, they may be looking for more treats... in the wild when the bite or chew on trees to get sap or gum they bite until they get some, when they stop getting sap or gum them bite again. So if you give them licky treats like honey or applesauce reload the treat after 3 licks. If you just stop giving them the treat after the first treat is gone they are going to bite looking for more. So if you only give them a little and stop, don't let your hand linger without washing your hands.
Might be a stage, give them safe things to chew on, like plastic drinking straws or a honey stick.
What ever you doing, when they bite, try doing that differently to see if their reaction changes to a positive one with no biting.