"나긋나긋하게 내게 속삭여"
- 나긋나긋하다: 1) soft and tender 2) gentle, flexible, accommodating (of a manner)
- 내게: to me
- 속삭여: imperative form of 속삭이다 (whisper)
So it may be translated as "Whisper to me tenderly and gently".
나긋나긋하다 is one of the many "direct imitation" words(onomatopoeia) in Korean - a class of adverbs that describe a shape, manner, or sound directly.
ex) 물을 첨벙첨벙 건넜다 / 바람이 솔솔 분다 / 목숨이 간당간당하다 / 나뭇잎이 우수수 떨어졌다 / 가슴이 두근두근하다.