I teach 4th grade.
A very important part of my relationships with my students is affection. A lot of my students may not have anyone hug them all day. It is important to me that I can give them plenty of affection throughout the day in my classroom. I also want them to feel safe and comfortable with me and much more willing to embrace and share affection.
One way I ensure that we have some type of contact during the day is as they leave the classroom at the end of the day I stand in the doorway and say, "high five, hug, or handshake?" and the kids know to pick one. Some kids just immediately hug me and some prefer the high five, then there are some of my charmers who consistently do all three.

Now, I have been cautious to give my 4th grade boys side hugs, because let's face it, I am a young teacher and they know it. Some are so tall side hugs are only appropriate. Some are still so small I have to bend over to hug them and or they hug me around the waist.

Today one of my most entertaining, sweet, talkative, loving, and quite small male students was hugging me in the doorway. He was full on around my waist and said "I just love hugging you!", I said, "why?" and he said, "you're soooo soft". Hmmmmm. I need to get back to side hugs.