The Collaborative International Dictionary of English v.0.48:

Snug \Snug\, v. i. [imp. & p. p. Snugged; p. pr. & vb. n.
   Snugging.]
   To lie close; to snuggle; to snudge; -- often with up, or
   together; as, a child snugs up to its mother.
   [1913 Webster]