My daughter self-weaned at about 2.5 years old.
But along the way, I talked to her about it.... she is a big girl, one day she won't need to drink from Mommy etc., I taught her 'manners' about it and that she can't just lift up my shirt or demand it, never in public, only at home etc.
Then sometimes when she'd ask... I would simply say "In a minute, Mommy is busy..." then I would NOT sit down and make myself 'busy.' Then she'd forget about it and get distracted.
For both my kids, I let them self-wean. My daughter did and my son did at about 1 year old. Each child being different.
Then, my friends, who did extended breastfeeding and their kids were 2.5 years old.... what they did is this: they put Band-Aids on their nipples and told their child "Mommy's milk doesn't work anymore...." or, "Mommy has a boo-boo...." and they said that worked for them. Very well.
My daughter, just one day out of the blue, told me "I don't drink from you anymore...." and then she giggled like it was so funny she did that. And that was it. All done.
My son, would literally slap my boobs away and scream when I tried to nurse him.
By this age... the child is not nursing a lot nor frequently. AND the body's production of milk... lessens. Adjusting to the child. So, you really don't have to worry about getting engorged or anything... I never got engorged when my kids weaned. By then, my milk supply was reflecting their so called intake and frequency.
All the best,
Susan