Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
snugly [ˈsnʌglɪ] adv ую́тно
to fit snugly (object in pocket etc) удо́бно помеща́ться (impf)
the sweater fits snugly сви́тер хорошо́ прилега́ет
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.