Stroke it ever so softly and turn him on. He will get horny.
Yes, that is the natural color of a dog's erect penis.
Does your dog have a penis? If yes, then he's a male. If there's no penis, it's broken. Return it for a new dog.
A male dog will have a penis.
my penis!
The male dog would have a penis
WHAT????
First of all, WHY ON EARTH WOULD YOUR PENIS BE IN A DOG?! and secondly, I recommend some form of lubricant.
if it doesn't have a penis
Get him neutered
the male sticks it's penis in the female
The same as the penis of any other mammal; to pass urine and sperm.
If you mean, "why do dogs get tied together when they are mating", well, the canid penis has a little extra feature called the bulbus glandis. When the dog's penis is erect, the bulbus glandis looks very much like a ball-shaped structure near the base of the penis and about twice the width of the penis shaft. (It is -not- the dog's testicles; those stay right where they're supposed to be.) When a dog mounts a bitch, he inserts his non-erect penis (supported only by the penis bone, the baculum) into her vagina and thrusts while his penis becomes fully erect. During this, the bulbus glandis swells, locking the dog's penis into the bitch, and soon afterwards the dog begins to ejaculate semen. The two shift so that they are standing rump-to-rump and stay locked for 2-40 minutes, during which the dog continues to ejaculate. Eventually, the dog's penis detumesces and the bulbus glandis shrinks, allowing the dog and bitch to separate.