SNUG

[adjective] snugger, snuggest - (of a person) feeling warm, comfortable and protected, or (of a place, esp. a small place) giving feelings of warmth, comfort and protectionWe curled up in bed, all snug and warm, and listened to the wind in the trees outside.I bet your feet are nice and snug in your fur-lined boots!I like the smaller room for the winter because it's nice and snug with the fire blazing.Snug also means fitting closely.That green skirt is a snug fit now but if I put on any weight I'll never be able to get into it.(humorous) '(As) snug as a bug in a rug' means feeling very warm, comfortable and protected.