Morning

I'm no dog expert, but I do take my Bonnie to dog training classes.  It sounds as though your dog is excited.  Excited at the thought of going out for a walk. Labs (from what the girls say at the classes) need a lot of exercise.  Does doggie play with a ball?  My Bonnie loves playing with her ball (but doesn't 'give it up' easily).  I now play ball with her, with two balls.  Throw one and have the other ready for when she comes back and she can see she's got another ball to go and chase. Whilst she's chasing the second ball, quickly pick up the first one... and so on. It was only by trial and error that I found this method worked for us.  Bonnie sometimes pulls when out walking, but I just give a short, sharp pull on the lead and tell her "No".  This may have to be repeated over and over again (I get fed up with it sometimes).  But if they know what the 'routine' is (i.e. playing ball or with other dogs), they'll toe the line.  As I say, I'm no dog expert, it's just  been trial and error. Hopefully, a qualified dog trainer can sort out your situation.  Good luck. 

Wilber xx
p.s. Using a Halti will give you more control when doggie pulls, and I found it gave me confidence (and kept me upright    ) when I had to correct her.  Also, don't forget, her 'routine' is off kilter whilst staying with you.  It's a holiday for her and we all know how excited we get when on holiday.!!