We have a 4 month old labrador st bernard puppy we've had him for about a month now. And he is just such a biter! (not nips) whenever he gets at us he's drawn blood. We have now taken him to doggy daycare weekly in hope that he learns bite inhibition. With us we've tried yelp method which just riles him up even more. The time outs aren't working because as soon as we enter after a while he'll just start up again. Our trainer told us to get him tired. The problem is, he gets really "vicious"/"excited" then he goes after our pants. He won't let go and starts growling, lunging, showing teeth at us. He's torn at our clothes and bit us with small puncture wounds already. When we see that he's about to go after our legs we say no bite! and try to move away but he won't listen and will just get at us.
When he gets all riled up we try to calm him down but its just no use because he's constantly going at us and lunging at us.

when we go out say to the mall or petstore and vet he'll just get so excited and start jumping and get bitey with other people just ends up hard to control. How do we deal with overexcitement?

In the mornings we take him out for a walk around our condominium area for about 30 mins, and at night. During the day I work with him in short bout of playtime and training sessions in the condo if he won't go at us. Basically its us taking him for a walk just worried that he'll lunge and bite us. Usually the walks just end up with me dragging him home with with clamped down on my pants or legs.

I would really like your opinion on this because asides from this issue he is a really good puppy. I'm just at a loss already.

So I want to know to deal with this issue? Many people have said this is a "dominant" issue. And that I should be the "pack leader" *rollseyes* but they do not give specifics. We've done methods such as he must sit whenever we go somewhere and needs our permission to get out, have meals and etc. Which he's doing good at.

Vets and some friends have told me to hit him on the head or snout. Which I do NOT want to do!