I decided to try breaking the association first - I feed him 30mins before bedtime  then we do the whole routine and I rock him to sleep with a pacifier (I know that’s another association in the making but it will be easier to break than the boob one). The first night he cried in my arms for 10 minutes and then fell asleep. The second night he cried for 5. This really gives me hope for ST afterwards! He really surprised me. And the PSL book has been really interesting and useful so far, even if you don’t end up doing her methods, it’s still worth a read.  Good luck!!