Warm and it smells nice. Your head gets all swimmy and you want to stay there forever enveloping her small, feminine frame. If the hug is long enough you will begin to get concerned that you ruined the moment with your boner, and you feel really self-conscious. Then, testosterone hits your brain like a freight train and you want to ravage her little body with your spear of meat. That's pretty much every hug I've had with a girl.
Hugs are amazing! as a girl, hugging a girl is fun, however if she's shorter than I am, there is a risk that she will be smothered by my boobs. But all in all, girls are comfy and most of us enjoy hugs...Hugs are my favourite!