When another small dog or person comes into the picture that stirs up feeling jealousy and insecurity there can be submissive peeing and other undesired behaviors expressed.
1 Place the new small dogs or persons items with their scent next to your current fur baby's bed,blankets, toys etc...
2 when your current small dog is sniffing the others scented items. give your current small dog a lot of praise lovey dovey baby voice. This is building a positive association.
3 The harmonious introduction choose a neutral location for the first meeting like a friend home or a park. This will avoid unnecessary tension if you bring them straight home first.
4 (If this is another dog) Have the current caretaker of the new dog brought to the decided neutral location. Place both dogs on leashes allow them to sniff each other. If the introduction becomes intense need your current dog away for a moment. Try it again.
1 What are the changes in your small dog's behavior? observe this. Examples submissive peeing, stealing food, growling at the other small dog or person.
2 For 2 small dogs, use separate rooms or separate areas to feed the two small dogs. This avoids aggressive food tendencies
3 Give both small dogs or person the same boundaries by treating them as equal as possible. If one is not allowed on the furniture neither of them are. Treat them the same as much as possible.
1 Provide plenty of toys chewies food puzzles. Things to burn off their energy give them walks every day. Keep him/her entertained and his mind busy
2 They're seeking a lot of attention ignore them. This reinforces good behavior.
3 When your small dog is calm and peaceful give them lots of verbal praise.
4 Create activities that they can do together or play together throw a ball squeaky toy hide and go seek.
Step in harness
Simon Forden, Demand Media