What does my dog's nightly "ritual" mean?

Every night before bed my dog (a spayed 2 1/2 year old JRT/beagle) will snuggle up to me and lick my hands and feet as if she's cleaning me. It's not her normal way of showing affection, it's like she's treating each of my limbs as a newborn puppy or something. She also seems like it's soothing or calming her. It's bot bothersome behavior I'm just curious as to what goes on in her little head!