Rolling over on back, legs in air - Let's play!
Rolling over on back, legs in air, whine - You're stronger than me/submission
Gums/lips drawn back (looks like a smile) - happiness
Lying down, avoiding eye contact, whining - I'm not a threat to you/You're the leader/I'm leaving! (used after threat)
Lying down, nose pointing down, touching ground, whining, ears flattened - basically, super submission, usually only used by rogue wolves who have just joined the pack. (wolves who are not very trusted)
Look to the side, avoiding eye contact, whine - You're boss/submission/sadness
Ears flattened, snarls, tail half between legs, fur on neck standing up - Fear, but if threatened it will still attack
Ears flattened, whine - Fear/submission/sadness
Ears flattened, tail wagging and head lowered - Friendliness, playful, submission (to friends of same rank)
Pointing ears forward - paying close attention, trying to hear information.
Walking stiff legged, shoulders hunched, tail straight down - Pissed off
Sniffing the ground, diverting attention - showing that s/he does not want to cause any trouble
Ears partially flattened and neck stretched out, tense posture and shudders, whimpers, moans, tail low, may be tucked in - anxiety
Move tail 90 degrees, pointing straight back - I'm not scared/I'm not moving/defiance
Tail wagging, mouth open, panting mildly - happiness
Tail down - submission to alpha, used at almost all times while with pack
Tail diagonal - caution
Tail curled up on back - alpha gesture (alphas only)
Tail between legs - fear
Tail slightly raised (45 degrees) - happiness
Tail straight up - signifies leadership (used by alphas), defiance to alpha (should never use in front of alpha!)
Step forward slowly, rub muzzles - Let's start a pack together. (love)
Step forward quickly, growl - Leave. (polite)
Step forward quickly, bite/snap in midair - Leave now! (threat)
Step forward quickly, nip at paw - Get out! (angry, about to fight)