A hug friend (sometimes referred to as a hug buddy) is similar to a fuck buddy. However, unlike a fuck buddy, the hug friend is only for hugging. You can call him or her any time of the day (similar to a booty call) to request a hug when you are lonely, depressed, or just want a damn hug.
Hug friends may hug while scantily clad or even naked, so long as their contact is strictly of a hug-like nature. Any additional touching of a sexual nature is considered a breach in the hug friend code so that the relationship may no longer be classified as a hug friendship.
"Yesterday I had a really shitty day, so I called up my hug friend, Mike, to request a hug. He came over and gave me a big cuddly bear-hug. Afterwards, I felt so much better."
"Room mate 1: So you went over to Amy's pretty late last night.. Did you guys do it?
Room mate 2: No, we're just hug buddies. She couldn't sleep because she needed a hug, so I went over to give her one."