Chill guys ... Its not that im bothered with that ... It was just a question !! Coz my friend was showing off that her shepherd is well trained and so smart that she was able to train her to keep her tongue inside !! So i was just wondering about that thing only !! No need to get that offensive
I'm sure that the op's friend isn't forcing their dog to keep its tongue in its mouth for extended periods of time. All that they taught their dog was to close its mouth. The are lots of tricks that you can teach a dog that are probably mildly uncomfortable for the dog. Standing on two legs, riding a bike, etc. Doing something as natural as closing their mouth really isn't that horrible so long as they're not forcing the dog to hold it for long periods.