Question 1

I would like to write to you about my male dwarf Dachshund who has 2 and a half years. Yesterday, he was trying to have fun with someone from my family in him throwing a bone plastic and at a given time, the person has sought to catch (wedging) the dog to the toy and the latter has bitten it hand. For me, the dog was simply taken aback by the reaction of the person. A few months ago, pretty much the same thing has occurred, a person amused to run after the dog and it has managed to take it by behind, so by surprise. Please give me your opinion on this subject.

My answer

It is always very dangerous to put a dog in a situation or there will be no possibility of escape, even by game.
The reaction of your dog is, despite the bite, quite legitimate. Your pet, by fear and unable to flee since 'stuck', did as last resort to keep the bone to bite with no doubt before grunts, beginnings of a prominent bite. In addition, the game has to create in him a certain tension by the excitement of the people playing all around, encouraging the dog to defend "at all costs" the coveted object.

In general, to a situation which makes fear, any dog will have several reactions depending on the context:

He will choose as a priority, if he can, the escape to get away as quickly as possible.
If it cannot flee because only hampered by a leash or stuck between two furniture, it can be stopped.
It can also, in the case of a real impossibility of escape and if the person persists in wanting to catch it (or resume which he owns), Growl to warn that it would be dangerous to continue further. If nothing changes, despite his warnings (grunts), the dog as ultimate will use eventually bite so that the situation ever really, can no longer escape.

What is important to know also, it is the reaction that you had at that time, towards your dog: the have you corrected? Do you have trivialized the event? You insisted again?
It is obvious that it is better to trivialise the event as your dog has had a legitimate reaction (for him), twist them back to this (too bold by lack or bad information) person who went beyond what the dog could endure emotionally.
As for the bite, it was serious? Was this just a pinch? A strong mark on the skin of the person?

The game must have its limits (in the first place because it is you who must decide the end and not your dog): it creates without that people notice, a tension in some dogs very sensitive emotionally, that risk too much to disturb the animal. I do not know your dog, but assuming it is sensitive emotionally, it is better avoid 'play' too long with him. Free game should rather be reserved for dogs between them, it's more in the end, a way for them to position themselves sometimes hierarchically each vis à vis other.
And especially take the time to explain to this person (a child?) that should never be stuck a dog even by game and especially not seek at this point out it, or to enter which he defends, or even enter it by surprise, without the dog could anticipate. You yourself have seen such acts consequences/damage!
If you want to resume an object that your dog will be caught, made diversion with a treat for example or even désintéressez him, doing something else or change room, he quickly abandoned its outlet.

It is good to respect the nature of the dog, and to know in our actions and human reactions, which allows or no longer allows the dog to adapt to the context of life that we propose.
I remain at your disposal if you want to learn more on this subject.