"The sun is warm" is a children's song, and there is a lyric "The sun is warm and the flowers are laughing". Although this sentence mentions the jumping action, there is no fixed rule for the specific dance action. You can design dance moves according to your own creativity and preferences.

Here are some suggestions for your reference:

1. Dance step: You can try to jump up and make a big jump when you are in the air, such as kicking your legs and turning around.

2. Swing action: You can swing your body and swing as warmly as the sun, such as shaking your arms left and right or twisting your waist.

3. Smiling face expression: In the process of jumping, keep a happy expression and smile like a flower.

In short, it is important to enjoy the dance process, give play to your creativity, and jump out of your own "warm sun" dance according to the rhythm of music and the artistic conception of lyrics!