Problems Left Right And Centre

[Ezy03]

hey guys n girls, iv got a shiba inu approx 6 months old now. he has been socialised with my friends dogs (2 or 3 or 4 of them - diff owners) and his alrite with them, for the past two sundays a friend and me decided to go to the dog park, his dog was fine...on the other hand my dog i let him of the lead as you do and he just went into a brawl, i put him back on the lead (used a choke chain), every dog that came past mine that wanted to play my shiba had no bar of it and just growled and huffed and puffed and went ape and started barking and biting (but i didnt let pulled him back with the choker), both times he was doing the same thing and not wanting to play like the rest of them. anyone know how to fix this problem because it became very annoying and all day he kept snapping at other dogs and only would play with my friends dog even that it was playing then it turned into dominace and humping my friends dog. with people his alrite doesnt bite or bark just licks and plays, but there was an incident we he just bit anything when he was getting agro while other dogs were around - took a shot at me too...

thats it for now, any help would be great.