Dogs demanding attention ( especially physically as you described) are IMO "assertive" dogs, shall I say, ones that have a fairly high self image of themselves. 18 months is the prime age for many a dog to test its previous boundaries especially if the dog is wired that way. Up the obedience and you should always be the one who dictates when attention is given, not the dog. When the dog is pushing you for attention/"affection", at the very least, make the dog earn it via obeying some basic obedience commands or other trained behavior.
Working for food is a common mistake so many make as it undermines the true goal of a working relationship. Create a relationship where the dog engages you because of what you offer other than food.
Being "harsh" at times only works if you back it up from square one and at exactly the proper moment. You sound like you have a willful dog going through a phase BUT this one sounds a bit more determined than your previous dogs. Up the ante and make the dog work for everything and I mean everything. You might ignore the dog for a while as well. If your dog knows the behavior then make him do it for your praise and expectations as well as what gets him next and I'm not talking about a scrap of food.
Do you currently do any focus drills where the dog must make and maintain eye contact before being released to a resource you control?
Investigate NILIF training and as you employ it, take your dog to a new level where he works for you, not a scrap of food.
Working for food is a common mistake so many make as it undermines the true goal of a working relationship. Create a relationship where the dog engages you because of what you offer other than food.
Being "harsh" at times only works if you back it up from square one and at exactly the proper moment. You sound like you have a willful dog going through a phase BUT this one sounds a bit more determined than your previous dogs. Up the ante and make the dog work for everything and I mean everything. You might ignore the dog for a while as well. If your dog knows the behavior then make him do it for your praise and expectations as well as what gets him next and I'm not talking about a scrap of food.
Do you currently do any focus drills where the dog must make and maintain eye contact before being released to a resource you control?
Investigate NILIF training and as you employ it, take your dog to a new level where he works for you, not a scrap of food.