She rarely spoke, but her brother could 'talk the hind legs off a donkey'. [=he was very talkative]
It's rude to 'talk' [='gossip'] about people behind their back(s).
The dog stood on his 'hind' [='rear'] legs, begging for food.
(..) Does that mean I'm morally obligated to burn that lady's outfit? Oh, my God, that's Ms. Norbury. I love seeing teachers outside of school. It's like seeing a dog walk on its hind legs. Hey, guys, what's up? I didn't know you worked here. Yeah, moderately priced soaps are my calling. - You shopping? (..)2004 Mean Girls