Waist Hug is started when you meet a new person for the 1st time and you give them a "hello" hug, As you get closer to them you "accidentally" slip and your head becomes submerged into their crotch
. Many relationships have started this way.
I met Chrissy's lesbian friend Kelly the other day and I asked if I could give her a hug. She got a waist hug instead and she's been speechless from that moment on.