I know this is an old post, but wanted to say thank you to those that answered this. I've got a 6 month old mini donk jack, (just waiting for better weather for gelding) and he's so fun and lovely, but he grabs my leg, or my foot, or my arm sometimes. It's winter, so there's fabric involved. It's never hurt, but I know I need to make him stop, because he doesn't see me as authority, more as his playmate. I don't give him any treats, so it's not at all motivated by food. He's really just playing around, being affectionate, like a toddler donkey. I have just been redirecting him, or walking away when he does it. Saying "no, that hurts" (even though it doesn't), and pushing his mouth away. I'm wondering about grabbing his mouth in some way, but I don't want to go too far. Sometimes, to be honest, he almost holds my jacket like it's a comfort. I don't know if that makes sense. He was just weaned when he came to me, and he has playmates "on the way", so to speak. A 10 day old baby on the ground, and another on the way. But they aren't ready for playing, and the 2 moms aren't going to play with him. So I'm his donkey friend and mother. If he gets sassy with the mommas, they kick him, or bite him back. I don't see that as an option for me. It's not an "all the time" thing, but I want to nip it in the bud, before he nips me in the butt. Haha.