We thought we'd done loads of socialisation with our Am Staff puppy but we've recently found an area we were a bit slack with - tall, adult males.

We have a friend who comes round pretty much every week and Mr Bear won't stop barking at him.  He settles down after a bit if he the friend is sitting down but mostly he just barks and slinks around him with his tail between his legs :(  Our friend is great and ignores him and lets him get on with it but the constant barking is driving me nuts.  We've tried putting Mr Bear away (he sleeps in the garage) and he forgets to bark but as soon as he sees him the barking starts.

If anyone can offer any suggestions I'd be greatful as our Papillon has now started joining in so we have one big dog bark and one yappy bark almost constantly.

Give your friend some tasty treats when he arrives, get him to encourage the dog towards him, when the dog approaches then throw a treat to the floor, or if he will take it from his hand even better. If he keeps repeating this it will hopefully build your pups confidence with him, as it does sound like your pup is barking through lack of confidence rather than aggression.

Are you sure this guy is OK?  My akita took a major dislike to my cousins b/friend once and made a point of letting me know he hated him and didn't like him in 'his' space.  He would sit in the way and not let this guy make eye contact with me to the point that we looked like we were watching a tennis match round him!!  This guy turned out to be a right git, much to our disgust, but I swear that dog sneered and said "I told you so!!".

If this guy is OK, I would go down the treat route.  Bound to win any dog over!

Give your friend some tasty treats when he arrives, get him to encourage the dog towards him, when the dog approaches then throw a treat to the floor, or if he will take it from his hand even better. If he keeps repeating this it will hopefully build your pups confidence with him, as it does sound like your pup is barking through lack of confidence rather than aggression.

Like this, though I wouldn't try to make your dog approach him! I would just get your friend to throw the treats sporadically near your dog (without looking at the dog or seemingly taking any notice of him), once the dog is braver and less worried, then nearer to himself until the dog is happy to take from his hand with eye contact. Do this with any visitors where he shows a little worry.

It is very important that you do not force the puppy into meeting and approaching people as that will make him more fearful! Just make him understand with food that having male visitors is a fabulous thing to have around and in his own time he will come round and will find his confidence with them.

I'm sorry to disagree on this. I have a now 9 year old male who has always barked at my neighbours son. The son only visits every few months, but he stays for weeks, due to his work. My boy took a dislike to him and will bark the minute he knows he is around. We have tried everything in the past and it is only now, after 8 1/2 years, that my boy has started to go towards him close enough to get petted. He still isn't totally happy but is starting to chill out around him. The son is one of the nicest men I have met. Totally trustworthy, and has helped me with my other dogs in the past. Some dos just take a dislike to some people, the same as we do.

However, in saying that, there is no reason why treats, etc won't work on the OP's dog. If it doesn't then they will either have to keep the dog locked away when this visitor arrives, or ask the visitor to stop visiting.

Just wanted to come back to this with an update. 

On Christmas day our friend (Elmo) came over and Mr Bear spent most of the day lying under the table at Elmo's feet and then on the sofa with us watching TV. 

We took things really slowly and made Elmo as non-threatening and exciting as possible and it's worked - they're now firm friends and Mr Bear is the first one to get a cuddle and a head rub whenever Elmo comes round!

The papillon takes his lead from Mr Bear and while he's not as over enthusiastic to see Elmo he's stopped barking at him and will lie on the other end of the sofa without any problems - Mr Bear will lie in Elmo's lap!!