This is common to the early learning curve. The dog knows either by years of gene knowledge he wants to point, you have encouraged him to point. He is excited, gets into to the crouch position to avoid flushing the bird. He undoubtedly hears you behind him, and can't see you, which is partially the problem. First, go alone, no people who cause need attention to the dog. Use a reliable bird, get a point/sit down/lie down, use calming reassurance and contact with the dog, go to where he can see you and the bird, right infront of the bird is best. The dog will be sure you are going to flush the bird, go to the dog, will stiffed up, and possibly regain his point, do not flush the bird, get to the dog, encouraging point, good boy, et.al. Get your hands on the dog, go all over him with you hands, stiffen him up, even by pushing him towards the pressure of the bird, get his tail right and pose him as you want him. practice, eventually, he will learn that with confidence in the pointing routine, he can stay up right. Ocassionally, I have seen excellent dogs, underestimate distance and get down to show they are right on top of a bird. With pups get the hands on him, reassure him, problem solved. If it gets dicey to get to the dog, because he runs in and flushes the bird, use restraint by a check cord, behind him ground stake, looped around you to enforce whoa. If the dog elludes you, and gets to the bird, flushing or getting a hold of it, it's not the end of the world, use as a teaching session, and get a good retrieve, praise him up, the go back to the sight of the point, setting him up as a point, make stay that way, praising him. Go on to other training. Make it a good session with young dogs. I have seen this a million times, sometimes I like a hesitant dog to one that bat out of hell, flushes, and goes on runabout. The hesitant dog has brains, encouragement is all he needs, the other idiot, may need to have to be ground down, it's ehausting and a task I don't like. Tell us the results, I am sure this will cure it.