As a lifetime sub i was always hesitant to ask any prior Domme for a reference. But, NOW, my sub life is dramatically changed. As She offered in this forum, Mistress Ayn is very reference friendly. As HER slave, i would never reach out to a Domme unless i had Mistress Ayn's blessing, which makes Her reaching out to the new Domme easier. i am SO contended with having a single Alpha Mistress that seeing a new Dommes is only due to location or if She offers some additional training for me.
But, thinking about it, subs, we have the luxury of reading a new Domme's website so we have been introduced to Her. Some subs are less eloquent in introducing themselves and then there is the issue of authenticity.
A reference is an important opportunity - please coordinate that with your past Domme. It will lay a stronger foundation when seeking to serve a new Domme.