What I do to make them 'tame' is holding them about 3 times a week for about 10 to 15 mins. Also I do not pick them up in the beginning when they are in their hideout, this way you do not disturb them while sleeping or when they allready feel agitated/stressed.
This should minimize the impatient reaction you get.
When they are adjusted to being picked up now and then, it will be fine to take them out more often. But keep in mind that too much is never good.