Does the following sound familiar?

"It's OK when my dog jumps up on me when I get home after work, but he also jumps on my guests, or he jumps on me after coming inside from the rain and his paws are muddy! How do I teach him when it is and isn't OK to jump?"

Or how about this one...

"Sometimes I like to play rough with my dog, but sometimes I want him to play gentle and he nips and bites! It's also embarrassing when he plays too rough with other dogs at the dog park and they yelp in pain. How do I teach him when it's OK to play rough, and when he should play more gently?"

The short answer: You can't.

Dogs are not reasoning creatures like humans. They do not understand "sometimes" and "maybe" they only understand "always" and "never"!

If you let your dog jump on you as soon as you walk in the door, and you reward that behavior with loving hugs and an excited tone of voice, you are telling your dog that it's OK to jump on ANYONE, ANYWHERE, for ANY REASON. Period. This includes on your guests, or after coming in from the rain with muddy paws, or even because you have something he wants like a plate of food.

The same goes with rough play dogs must be taught limits during play. Otherwise they never learn the consequences of biting or mouthing too hard. If you let your dog play rough with you (lots of scruffing, roughing, shoving, biting and even smacking), you are teaching your dog how to play, period. If your dog doesn't learn limits from you, how do you expect him to respect the limits of other people or dogs (or your own constantly changing limits)?

Remember: Dogs don't understand special situations and exceptions to the rule. If you don't want your dog to jump or play rough sometimes, you must teach them to NEVER jump and play rough.