How do i stop a dog from sniffing everyones crotches?

my boyfriends dog toby is a flat coated retriever. he is 8 years old and he sniffs everyones crotches male or female.
i cant stand it and some people avoid going to my boyfriends house because of it.

how can we get him to stop?

ive tryed tapping him on the nose and saying no! but he just keeps doing it.
apart from that he is a really nice dog.
Answers:
Yes.sounds like you guys can try spreading some strong odor/smell in these area where he like to sniff.so he will get a nasty surprise when he is doing that.Please keep doing that for a few days.I know that you guy can see the differences(of course.you guys need to know what smell your dog doesn't like first.)
let him have a lick - he'll never return
Get cleaner friends
Smack him in the head with a crowbar, he'll stop doin' much of anything. I did. And for some stupid reason he kept sleeping, so I sold him to some blind. Hope he didn't mind the flies.
jk jk jk
perhaps getting folk who visit to liberally apply after shave/perfume to their crotches before they visit to disguise the smell of stale urine. you could even have this available for visitors in your hallway as they enter, but keep your eye on them as they may steal it
Thank goodness my dog doesn't do that! Just persistantly push him away firmly saying "NO". This has to be done EVERY time! He'll get the message.
If you know guests are coming maybe you could put your dog in a comfortable room for it or tie it up. All dogs do it big or small.
get there before him.
Don't kick the dog. Use a squirt bottle with water.
make your friends push him away and say no. seeing him coming in for the sniff and block him with a knee, eventually he will learn.
Reinforce the command `No` with a tap on the nose with a rolled up newspaper .Pull him immediately away and place him in a down position .
When a dog meets another dog they immedietly sniff each others bottoms and private areas. Dogs rely on sense of smell to tell them about the world around them. By sniffing a dogs bottom or genital region, the dog learns who the other dog is, how healthy they are and if the other dog is female, whether or not it is ready to mate.

Some dogs don't realise that humans are offended by this manner of recognition, because to them its natural to sniff someones genital region because that is where the strongest smells are. In fact the dog is probably offended that you don't sniff his bits in return! In humans we have scent glands on the palms of our hands and the soles of our feet. Try offering the dog a hand to sniff instead. Everytime he sniffs a hand instead of a crotch praise him. If he goes for your crotch instead, don't smack him or drive him away, just completely ignore him. He'll soon associate attention with hand sniffing, and non-attention to crotch sniffing. Of course you will have to get visitors to treat the dog in the same manner.
Make a joke of it while warnng your guests to protect themselves!! After all, it's natural. We humans have developed such silly modesty and manners.
get a water spray bottle with straight water or even mix a bit of vinigar in and kindly spray near his face when he does it. this method can be used to stop all bad behavior. it may take a bit but it should work
some dogs do this. i think its because they sniff other dogs privates when they meet a dog, this is their way of getting to know someone. people shouldn't be that offended by it, the dog is doing what it thinks is ok, so in order to get rid of this behaviour, push the dogs nose away gently when he goes for that area and say no, if he obeys pet him and say good boy. reward good behaviour, good luck!
Frankly, u can't really stop him, cos dogs go about recognition from smelling other dog's ***. He will do the same for humans. Sometimes they are too 'friendly' and pumps on human's legs, be it guys' or gals'.
I usually 'scold' my beagle, and he'll kinda stop doing it. But he will go to another person or go BACK to the one that he hasn't finished sniffing once u're out of sight.
Maybe explain to friends that it's natural for dogs to behave like that. Let it sniff to know u, after that he'd be OK.
Put a shot or two of black-pepper on every-ones crotch for a while..that may end his crotch sniffing ..But really do you know why he dose it? They say dogs can smell if there is any illness or disease inside of the body of the one it is sniffing!!They do this to prevent the spreading of any contagious germs/viruses etc.I say let him sniff all he wants.stop him when he starts taking full bites of peoples crotches!!
Train him that before you open the door he goes to sit on his favorite doggie bed. So before you even open the door that is not an issue.. when he meets someone have stamd tjere amd asl jo, to sit and wait (not he is not allowed to stand and sniff) and then have them give him a treat. Soon, he'll concentrate on the treat.. when he is done with the treat he should be taught to go back to 'bed'. Ask a few friends to help with this training. Have them come over, and help out.
it is a hard thing to teach a dog seeming that's how they get to know you so try having him on a leach and keep him beside you.walk over to your friend and get him to smell their hand not the grion.if he goes for the grion pull him back and say no firmly.
ask your boyfreind what he has been upto.,.. has he let the dog sniff/lick his crutch? and now the thing thinks that's normal..
give him a taste of his own medicine. sniff HIS crotch and see how HE likes it ;)
Well if you think about it your boyfriend's dog is just behaving naturally because dogs do sniff other dogs bums because this is the way that they say hello and it also aids the sniffing dog to identify the other dog through scent for example is the dog male or female.

You really can't stop this behaviour believe I've tried because I have two dogs and one being an male Irish Wolfhound and they have a thing about sniffing peoples crotches just like your boyfriend's dog but the only thing you can do is to push the dog away when it tries.

Male dogs are more known for doing this behaviour.
Get cleaner friends, if there's nothing to sniff the dog won't do it
as long as he doesn't lick them.