Reddit mentions of Loving Pets Pure Buffalo Meaty Femur Bone 46" (2 Pack)

I'm not entirely sure why the cooing at toys would work. I feel like this is just anthropomorphizing the toy and your dog's "understanding" of the situation. If it is actually working for you, it's probably the fact that you are taking away the toy from her, letting her settle, and then returning it when her energy level/fixation are more in check. The "gentle" cue is definitely nice to teach, but it is probably working due to your addition/subtraction of reinforcer. That being said, "gentle" is a tough thing to teach some high energy dogs so props to you.

Also, the exercise thing is a great point. If you exhaust your pup with a good run or hour at the park they will be far less destructive in the house. Physical stimulation and mental stimulation need to go hand in hand, and one should not replace the other.

Just a point to bring up: if your (OP's) dog is chewing things like wires, socks, etc. he probably has a lot of opportunity to do so. How are you managing his environment - supervision levels, puppy-proofing, movement throughout the house, restriction when unsupervised (crating), etc? You need to minimize or eliminate as many possibilities for your dog to "mess up" as possible and set them up for success. For example, make sure he is in "puppy proofed" rooms with all foreign objects picked up off the floor and is provided with appropriate outlets for his energy (Kongs, stuffed bones, etc). A six month old puppy probably should not have free run of the house just yet, especially since he is most likely still teething and is still learning appropriate outlets for chewing. Slowly increase his freedom once he has learned these things. Start by keeping him in one or two rooms, gated off, and slowly increase his freedom once he learns more appropriate behaviors and has matured a bit more. Am I suggesting condemning your dog to a room for life? Absolutely not. You just have to manage his environment as much as possible and eliminate possibilities for him to fail.

It would also be worth investing in some brain toys to drain more energy, such as Wobble Kongs, Busy Buddy feeders, Buster Food Cubes, etc. In fact, feeding his meals exclusively out of these toys rather than a bowl would be a great opportunity to mentally stimulate him and drain more energy. Just make sure you supervise him as some of these toys could definitely be torn up if left unattended.

Just some food for thought. Hope you found this helpful! :)

Edit: Some products I've found helpful.

Brain toys for feeding:

• Kong Wobbler for meal times. Pretty durable and my guy can't figure out how to open it. Loves eating out of this thing, even if it was simple for him to figure out. My lab took weeks to get it though. Regardless, great brain-toy.
  
  
• Buster food cube for dispensing. Pretty difficult to figure out.
  
  
• Busy Buddy Kibble Nibble egg: My guys LOVE this, although the plastic just cracked on the inside after a few months. Can definitely be torn apart if left alone but super stimulating and engaging. Worth it!
  
  
• Tug a Jug for keeping them busy when you need to do something else. Durable bottle that gets scratched up. Ours is a few months in and still kicking.
  
  Chew toys:
  
  
• Kong XL for stuffing with RB, wet food, boiled chicken, etc. Strong than the regular red Kongs. Can also be frozen which increases the difficulty and time needed to get the food inside. have several I rotate out and they are basically the same shape as the day I bought them, which is impressive as my pup is a monster chewer.
  
  
• Filled thigh bones are pretty nice. They last as a while and can be rinsed and restuffed if the bone is still in good shape. Watch out, though - some brands are more prone to cracking and splintering while others last for ever. Trial and error basis. I can't remember the brand I use that works well but it's carried at my local Farmer Supply store (I find the bones and toys at these places to generally be better quality and also cheaper than chain pet stores).
  
  
• Meaty thigh bones are marrow filled and still have some "meat" on the exterior. They tend to last longer than the washed filled variety (above) and are "stinkier" and (I would imagine?) tastier. My guys prefer these to the plain bones since there are more goodies to get at. Downside is that they are a little stinkier at first and can possibly leave a mess, so make sure the dog is eating it on a towel.
  
  
• Bully sticks! Make sure they are real beef tendons though. Many companies make pressed rawhide varieties to resemble the real tendons but rawhide is, IMO, less safe for dogs. Last a while and smell like bacon but made my stomach a little queasy. Dogs go nuts for them though.
  
  
• Jolly Ball - not necessarily a chew toy but lasts a long time. Their teeth can penetrate the ball but the design is such that the ball doesn't pop. I had the variety with the rope that went through the center. The rope came off pretty quickly but the ball itself is still kicking. It is challenging to pick it up when playing fetch so he is less interested in tearing it to pieces than retrieving. It's poked through with holes but is the only ball that has lasted this long. Still going. Maybe worth checking out.