Those babies are so cute!
The teeth clicking I've read is called bruxing- and many times, ppl will say it's done when they're happy. I know they can do it when they're stressed, but if it's followed by 'boogling eyes' then they're happy (but it doesn't have to be followed by it to mean they're happy). It's actually funny to see. You can also try to 'brux' your teeth at your rat. I read a rat owner suggest, getting eye level with your rat, then bruxing your teeth (just click your bottom teeth against your top in kinda a rounded motion, not just up and down- like... click rubbing? So hard to explain... lol) and after a few moments, they will start bruxing back at you and might even eye boggle. Ultimate sign of rattie affection. I got my oldest to do it to me the other day, it was so cute. xD;;
They might squeak at some points, but it won't be any big deal if it's a little peep now and again. Mine will do that, but they're just playing (but one is older and he's still doing a little dominating thing xD).
