I'm dealing with a similar issue. My last pup did very well with the "Ouch!" method. This one acts like it's an invitation to bite harder, especially with my son. My new pup can be very sweet and gentle with me especially, as parus suggested, in the morning. . In the morning, she likes to snuggle and her mouthing is gentle as she falls asleep on my lap. If her mouthing turns to biting, I try to redirect her to a chew toy. This has taken many tries. Initially, she was not interested in them but if I hold them for her while she's on my lap, she'll chew them a bit. Other times, she's a little T-Rex, attacking my hands, feet and clothes with her needle teeth and sharp cat claws. My hands are dotted with dozens of scabs where she's nipped me while trying to put on and take off her leash. When my son comes home from work, she's instantly in T-Rex mode. I think she sees him as her personal chew toy.My wife has been trying bite inhibition with her as well, but to avail (at least not yet). Granted, we've only had her for two weeks, but it's confusing when Gormley does so well with me, but lose all sense of reason with my wife. It's as if Gormley sees her as a toy, rather than a co-boss
We've tried something new the last few days which is helping a little bit. I motion her to sit, reward with kibble. Motion a down, reward with kibble, then put three more kibble on the ground and while she's eating I'll clip the leash. We're also trying the loose leash walking tip of walk and treat, walk and treat to lure her to the backyard and back into the house. This keeps her from attacking our legs and feet as often.
Tomorrow, I will pick up some bitter apple spray. I plan to spray the back of my hands to discourage my little land shark from eating me alive.