Can I ask how you would handle this?

[Dieu]

My 8 month old Shih Tzu pup has separation anxiety. Mostly he just likes to be with someone, anyone, than on his own ... although his first choice would be me.
The other day my 15 year old daughter had him out on a walk, and I bumped into them as I walked to a friend's for lunch. Without thinking, I went over to say hello. However, when I left, pup went nuts. He was barking, refusing to move, snapping at my daughter (very, very unlike him) when she tried to pick him up. I felt awful as I knew how stressed both he and my daughter would be, but left them to it, as they were round the corner from our street (1 min from home) and I was running late. I also thought that if I went back, it would smack of rewarding his behaviour.
I'd really appreciate any tips on how to deal with this. I am due another visit from our behaviourist soon, so definitely one to bring up with him.
Many thanks.

i would rely on the behaviourist that has already worked [successfully?] with your ddog, as they know all their ways and potential causes/personality best.

I think recommendations here could be wider of the mark than someone who's actually met your ddog and already started working with him.

I do teach mine quite young (part of lead training/socialisation) to be able to stay tied to something whilst i walk away (how else do you manage the school pick up and other things). They have to watch me walk a short distance away (initially) and then i go further and for longer, they learn that you always come back (but i am extremely careful about where i would tie them, and do it uncommonly, only in need with known others around, never leaving them at theft risk).

do you also leave your dpup for short spells indoors alone?

This is essential, even if there's no particular requirement for you to leave it behind when you go out, its better for the ddog to learn to manage itself, obviously making sure its been walked, fed, watered and given ample chew toys in its familiar bedding, etc. then leave for short spells. this could even be to another room in the house to begin with.

It seems that your puppy is insecure about when - or even if - you'll return. I think you need to build his confidence in your relationship, in that he learns to know that you will always return to him.

When my girl was a puppy, I only used to leave her at first for 5 minutes or so. I'd go back into the room, stroke her and say 'good girl' in a sing-song voice. I'd gradually elongate the length of time, eventually popping out for just 1/2 an hour, then 45 mins, then one hour, etc. She can be comfortably left for approx 6 hours but I only do this 1-2 times per week.

There has always been the same acknowledgement when Ive returned; always a calm greeting. She's 11 now and doesn't bat an eyelid when we go out and she's calm when we return. She's always full and exercised before we go. She always has her bed and water near her. I always say 'I'm going out now. Be good!'

I hope you work out a happy solution for you and your boy