Our corgi came to us after my ex-husband died July 4th. Gumbo, 6 yr. old Corgi, is very much an Alpha Male. He gets along better than expected with other dogs but we've been having a problem with his moodiness. He can be a Jackel or Hyde. One moment he's responsive and loving, the next he can be standoffish with growling and snarling at my grown children. He seems to be very protective of me and we can't figure out why he growls and snarls towards my 23 and 25 yr. old that often have Gumbo in their care. Telling him no doesn't work. My son was told that this could be a dominance issue and that the dog should be put on his back until the behavior ends, then to praise him directly after he stops the behavior. Any suggestions? He's a great dog but this behavior is annoying and needs to end.