how tosimple smooth

how do i smooth this

body.position.y = body.position.y-0.1;

ive tried

body.position = Vector3 (body.position, body.position +1.0,smoothTime);

or even

body.position = Vector3.Lerp(body.position, target.position, smoothTime);

with last one i dont have a target cuz is constant movement transform

i did it

 Vector3.Lerp (bodyPosition.position, bodyPosition.position + new Vector3(0.0f,2f,0f), smoothTime);