The same as the penis of any other mammal; to pass urine and sperm.
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.
The function of the penis is for only two things: excreting urine and to copulate with a cow in order to produce a calf.
if it doesn't have a penis
Get him neutered
the male sticks it's penis in the female
used in reproduction