Lactating SPs hard to find.
How you would encounter a lactating SP or MP is by chance. I did meet one years ago. My guess is that she was going through hormonal changes.
I visited MP for a massage, but she included oral and penatration in the price of the service. While there was milk coming out of her breast at thr begining of the massage (a few drops of you squeezed the nipple) As she got all hot and exited later in the massage her breast realy produced. Most of the time I squeezed about an oz. out of each breast.