i was looking at archelon today and seen her playing with a rock.. she put the rock between her flippers and infront of her head, then began playing and pushing water to the stone. its like vibrating.. very funny!!
It sounds like your she is a he. Many male slider type turtles rub the face of the female with the back of the front claws. They will also vibrate them against her face. Just an idea from your description.
That's not how you tell sex on those. That applies more to box turtles and some torts. Can you take a pic and post it? Males are smaller with long front nails and a longer tail.
I just realized you were in Indonesia. What kind of turtle is it? I may be wrong. I was thinking you had a red eared slider or some other type of slider.
i think its a RES, its most common here. but i dont know, they said this turtle to be brazilian turtle, so.. i dont know what species mine is. but after i browse for some RES pics, they look similar, but i know some slider turtle are similar, but yaa.. dunno la.. thx..