For many years now you can hold the Jersey/pads as long as you stay within the frame of the shoulders. If you stay inside the shoulders, the only way it gets called is if you continue to hold after the play has passed and the player is trying to pull away to follow the play.
Huskerthom- Is absolutely correct in everything he said.
Basically if you have your hands inside the framework of the body & on the breastplate, it not only gives you the best position to win at the line of scrimmage, but you will not be called for holding. When your hands get outside the framework of the body that's when holding will be called, especially because a lot of times that's when the jersey starts getting pulled. The person with outside hand placement also usually loses the down & that's when shenanigans start to happen.
Nice, thanks!