Bringing a strange dog to the house

Tilly is not used to dogs coming to our house, apart from Dave the dasch from next door who she knows well & yesterday hub's friend was coming with his puppy (5 month) GSD.
I know from experience that she doesn't like GSD's, she is frightened of them but if one approaches her & is silly & friendly & young she will play once she's realised it means no harm.
So I wanted to be prepared & I thought the best thing to do would be to take Tilly outside on her lead to meet the dog first & then bring them into the garden together - avoiding the house. This went ok & we then sat in the garden with them on their leads & they both appeared calm, so I decided it would be ok to let them off their leads.
Big mistake! The pup approached Tilly & Tilly immediately went for it. Hub reckoned it was too soon and the pup invaded her space.
I know if we would have been out on the field the situation would have been so different & she would have gone into puppy mode & been friendly so I'm thinking this must be because it was on her own territory & now I've made the whole GSD fear thing even worse
(The puppy was fine, though she ran & hid in the shed) then the bloke put her in his van.

Oh I bet you could have cut the atmosphere with a knife, I can imagine you all sitting there on tenterhooks raising the level of tension into unbelievable proportions and the dogs being equally tense!

Try not to make this mistake again, it was entirely forseeable that a young puppy was going to be curious in the other dog and, from your post, also entirely forseeable that your dog would not react favourably.

Not a good experience for either you, your dog or the unfortunate puppy!

If you do not provide a dog with an oppportunity to retreat somewhere to feel safe and bring another onto its territory it is not surprising she acted as she did.

Hopefully this is not life threatening, I think you need to be more relaxed though and have out of house socialisation opportunities!

The friend was fine about it........ he & hub were quite relaxed, it was me probably sending negative vibes.

Out of house socially Tilly is fine, if she knows the dog, she will approach it, if she doesn't she will lay flat & wait for it to approach her & then either play with it or just ignore it & carry on. No other dogs come to the house except for Dave & daughter's friends husky (and that isn't often) so I can't see how I can get over it unless I grab a stranger with a dog & bring them home with us!

Is it necessary? I do not have other people's dogs in my house so I do not train for it.

they are fine in other people's houses with their dogs.

I'm inclined to agree with SB.
Mo would never tolerate other dogs in our house, out and about she was fine.
So I would just say to people, "sorry you won't be able to bring Rover, Mo won't tolerate him"
It is a shame but it's Tilly's house

yes I s'pose you are right & I see what you mean, it is her house (and the cat's)......... but I wish I've have had more dogs round now on reflection. We did when she was a puppy but not recently.