How long is a piece of string!
According to the reasearch by Kathy Dettwyler the antural age of weaning is between 2.5 and 7.
http://www.kathydettwyler.org/detwean.html
I believe in baby led weaning, they stop when they are ready but I do it for at least 2 years as recommended by WHO.
Anyone who thinks feeding a toddler or older is sexual or disgusting is sadly a victim of our societies obsession with breasts and their sexual purpose.
I know before I did it I thought it a little odd but once you are there feeding a walking talking baby it's the most natural thing in the world!