The proper way to drink Guinness is warm, just at or slightly above room temperature. As for me, I enjoy it both warm or cold, but it does go down smoother when warm. It is a bitter brew, especially if you are used to sweet, pale American beers that come in a can.
By its very nature, Guinness develops a thick head when poured from the tap. Personally I don't mind, but some do and go through all sorts of rituals to minimize the head. If it really bothers you, do what the professionals do and pour it off. The head is so important, that Guinness has jumped through all sorts of engineering hoops to design cans and bottles that release the head when opened. That is why there is a hard plastic, um, thingy, in each.
Finally, if you must chug, the Irish Car Bomb may be just the shot for you. Only attempt this if your goal is to get drunk, and get there quickly. Make arrangements so you don't hit your head when you pass out, especially if the evening consists of several of these delicacies. Fill a shot glass with half Irish cream liquor and half Irish whiskey. Then, feel a pint glass ¾ full with Guinness. Drop the shot glass inside and chug quickly, or the resulting head will soak you. Look at the pictures of your shenanigans the next day and enjoy.