our golden retriever loves dogs now he has found his feet, we always let him socialise on walks if other parties agree,  lately his has started to sit ages before the other dog gets near , i thought this was because he sits for meals, food, treats, lead on etc so i could understand this but on the last two walks he has started to lay down when dogs approach, today this other guy walking his two dogs said don't be scared to tyler then as soon as the dogs get near he is jumping on them like normal. I have never known this before has anyone else had similar experience with there dog. It's not a problem just wondered if there was any reason for this, as in play he is not a submissive dog.

As far as I know it's well within the range of normal behaviours. From what I've learned, in 'nature' it's often a prelude to an attack (hence the sudden launch) but in a well-socialised, good-natured dog the 'attack' is inhibited, and with other dogs equally secure amongst their own kind there's no harm done. However you need to watch the body language of both dogs carefully - if he does this to an aggressive, badly-socialised or fearful dog it could be misinterpreted and the 'recipient' might respond defensively with a fight being the result.

Our 11 moth old gold retr does this too, when he's lying down his tail is going hammer and tongs!

Unfort he also loves to terroris our cat doing this before he pounces! She hasnt fallen for it yet tho!!

My 19 month old retriever does this too, she is a very submissive soul, and truth be told a little nervous about other dogs. But if she is approached/approaches another dog she sits and bows her head, which i think is quite polite. SHe will then let them sniff her and if all the signals are right she will suddenly jump up and start playing. I think she is basicaly trying to tell them that she isn't a threat.

All sounds quite normal then, i see what you mean in some dogs they may take it the wrong way, will keep an eye it. I have to say he gets on with all the dogs we meet he just wants to play with them. Having said that we meet two on a regular basis and his behaviour is different, they go straight into play mode no introductions needed. I just found it a bit wierd as before he would pull the lead if he saw another dog and now instead he lies down. He is not a nervous dog at all, in fact now he is completely the opposite a little too forward.