"Mild" and "gentle" are two words that can describe something that is warm and gentle. For example:

The sun was shining and the breeze was mild, making it a perfect day for a walk.
The gentle heat from the fireplace made the room feel cozy and comfortable.

You can also use the phrase "warm and soothing" to describe something that is warm and gentle:

The warm, soothing water of the hot tub was just what I needed after a long day.

Alternatively, you can describe something as "comforting" or "cozy" to convey a sense of warmth and gentleness:

The comforting blanket wrapped around me pke a warm embrace.
The cozy fire in the fireplace made the room feel inviting and inviting.