copper iud

I got the copper Iud inserted into me on the 25th. 
I was put to sleep since I also had another surgery before that, I was barely awake and aware of my surroundings after, and the nurse told me something about my Iud. I was so out of it I didn't understand what she said. 
It was something about the string at the end of the iud, something like checking if it's there or just that my boyfriend will feel it whem we have sex. Something along those lines.
Do any of you women know what she might've told me? I'm scared she might've told me something important and I didn't hear.