The behaviour you are discribing is not an excitement based behaviour, nor is it a sexual based behaviour, since your puppy will not reach sexual maturity until around 6 months of age. This behaviour is purely a dominace based behaviour. It is common behaviour for puppies to exhibit whilst they are learning were they stand in our (family) dominace hierachy. However saying that it is normal does not mean you should ignore this behaviour. Your puppy is basically testing the water to see if he can dominate you. At this point we need to start to reinforce in your pups mind that you are the 'top dog' and those in your family must do this to, especially if you have children. There are many different ways to enforce dominance, and no of them need to be nasty or insight agression on your behalf - showing him your teeth for example. One of the most effective ways to reinforce the correct relationship between yourself and your new puppy is through obiedance training. Your dog needs a strong leader to feel secure within the household and avoid behaviours that steam roll into problems. Have you and your puppy joined a puppy school (see you local vet centre) or have your thourght about joining an obiendance school. Both these forums will help teach you how to build the correct relationshiop with your dog - YOU being the leader and the DOG being the follower, instead of the other way around. The training will also do wonders for your new pup in as far as socialising him with other puppies/ adult dogs/ children / adults/ different noises/rain/wind and heaps heaps more. Puppy school at your local vets is great because the pup will have a ball and will then assocaite the vets as a pleasurable place instead of a bad place. Also at puppy school there will be other people in your situation, and you will get valuable tips on how to stop puppy related behaviours, which you may already be noticing such as inappropriate toileting, jumping up, hyper excitement, mouthing, chewing, digging holes etc
I can not stress highly enough the importance of taking new pups to obiendance schools. Granted not everyone wants a dog that can do backflips on command but the spin offs of attending an obiendance school even if not for the rest of the dogs life, are well documented and recognised with the veterinary industry.
Some things you can start doing at home are as follows:
A) Always feed your puppy last (after you have eaten if possible) but definately not when you are preparing you food. In the wild after a kill the alpha male and females eat first, then the rest of the pack according to hierachy (dominace stance with the pack)
B)Ask you puppy to do something for you - like sit or drop, before you reward him - either with pats, throwing the ball or feeding him
C)Cant think of any others due to tiredness - isn't that sad :D
Good luck with your new puppy. Owning a new puppy can be such a rewarding experience. If you have any other questions or need me to clarify any of this long winded reply, feel free to PM me.
Emma