hi My neice was about 18months when my sister decided she'd had it long enough. My niece was the same as ur son - only needing it and her wrap/blankie for bed time. One morning my sister cut off the tops of all the dummies in the house and showed them to my neice. She said to her "they're all broken now honey - but ur a big girl and don't need them anyway". My neice looked at the broken dummies and helped her mum put them in the bin. Since then she never needed them again (if she ever asked for it at bed time my sister just reminded her that they were broken and she accepted it). Even when i had my dd a few months after and she saw her dummy, we just reinforced that she was a big girl now and that dummies were just for babies. it really was a simple as that....i'm hoping i'll have the same luck when i get there!!!!!!!!!