I have 2 Maremmas... they are a year old now. Maremmas a very social breed of LGD and they LOVE to "hold" you. I however did not appreciate ending up with bloody hands from an over zealous pup that wanted to "hold" me so I would flick the top of their muzzles when they would bite me. It took about a week and they finally learned not to bite down. The easiest way to teach them not to bite is also teaching the the word "off" (I taught mine to walk on a lead, sit and lay down as well... it helps when introducing them to new kids or goats) Anyways teaching "off" is an easy way to get the biting to stop because they won't have that over excited bouncing, jumping on you puppy attitude when they are trying to hold you and bond. :- )
Do you have more than one LGD???? I've found it to be very helpful having more than just one.
I always popped mine up under the bottom jaw when they would try to nibble on me or anything else they weren't supposed to.
The other thing that i really reccommend is teaching "over" where they roll over onto their side in a submissive down. This was great for having to palpate for injuries, check bellies, trimming nails, or to teach that they are not authoratative to me. It has worked great. When I have new kids born, I tell Luna "over" and let the kids come check her out as they want and climb on her and it teaches her that she isi not allowed to chase those babies or hurt them.