Not having any experience with tegus ,except for my own gold, it's either one of two things.. They are happy... and they love you and they want to be your friend starting RIGHT NOW!
Or what the story was with mine.. he was very sick, and scared and just wanted to play dead, but I interpreted it as he loved me.. hehehe so now 3 months later and as better as he'll ever be (sans some toes from the inadequet care he recieved at the pet store (he is a rescue)), he is the fiestiest thing I've every seen and very whippy.. But on a happy note the darn thing knows me... So he won't bite me.. (I am ALPHA TEGU HEAR ME HISS) But my husband on the other hand won't put his hand in the enclosure period. (Finn doesn't like my husband.. don't know why but he gets the bipeadal-running-mouth-open-I'm-gonna-bite-you act)... So just for prosterity sake, get a fecal done on both of your tegus. It's much better to be safe now and spend the 50 bucks to get them checked and medicated if need be... vs..... not having them anymore and being worried sick the whole time they are dieing on you.... and the broken heart when they are gone. Sorry to be so depressing but I would feel horrible if I didn't take Finn in on day one when I rescued him.. because he would be gone, and I don't want that because I love him.. so I want to be the one to wring his neck when he's naughty j/k 
des