a warm welcome from me!!!! i only joined here a few days ago so im new too, training your boston to go outside should be easy without a doggie door. best method is to hang something noisy from the door (like some keys) within reach of your boston, he will have accidents, so when he does, tell him off and show him the evidence then take him to the door, jingle the keys with his nose and take him outside for a few minutes, works a treat with an intelligent dog, he should work out that if he jingles the keys he gets taken out and no telling off! also you can hear that he needs to go so no guesswork involved, good party trick too! good luck x

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love George xxx