Goes by many monikers. i.e. Awkward Lock; Pelvic Press.
When a dude goes in for the hug, but sneaks in a little pelvic thrust/hip grind action on a girls lower abdomen. Leading to a very one-sided uncomfortable pause. Guys don't usually know they do it.
"Oh My Gosh! Mary I haven't seen you for so long!" *Creepy Hug*