we get that too, she has her excited sprinkle pee & her submissive sprinkle pee. is he acting submissive (tail tucked, on his back, licking the other face, belly crawling) or is he dancing around happy to see you?
if he is dancing and playing just totally ignore him when you enter, have him in a different room when someone new comes in-just long enough for him to control his urge to get overly excited. Explain to your guests that they should not aknowledge the dog until he is being calm.
if he is being submissive, ignore this as well. if you praise (pet, soothe) while he is doing this, it could lead to fear aggression when he is older. it is his way of giving up, his own little "white flag". when you can see a dog approching that will trigger this behavior, encourage him to sit at heel and focus on you, training will help build confidence.