Just a little personal experience with long-after-weaning nipple
discharge... My youngest weaned almost ten years ago.  I still
have a cheesy white substance which can be expressed from both
nipples. Only stimulation is through sex, which may be 1-2x/week
on average. Everything seems normal. Both of my children weaned
at five years of age.

Still normal(I hope),
Sharon Knorr, BSMT, LLLL, IBCLC; Newark, NY