.. atm i print the tshirts, but every time i have gone to print on the necks the paint seeps through so it is visible when turned back out.Turn the shirt inside out. Print.
We'd be able to give you a better answer if you were specific with your question. What's the problem? Design? Or print? Are you outsourcing? Or doing it yourself?
Printing neck labels isn't all that different to printing the shirt in general. If you let us know which part is tripping you up no doubt we can clear it up for you.