Ask a master to teach you how to take this kind of photo with a SLR.

First, let the girl stand between you and the camera, do the action shown in the picture and keep still.

Second, put the camera on the tripod, put it safely, turn off all the lighting in the room, and the camera is in darkness.

Third, the camera uses M-gate and B-gate, preferably remote control, otherwise it is easy to shake if you always press the camera by hand, and at the same time you can save one person from pressing the shutter, hehe.

Fourth, please stand on the other side of the girl, holding a light stick, flashlight, etc. Turn on the power and wave it according to your idea. When you feel almost ready, turn off the power and stop the exposure of camera door B.

Everything is done, not to mention the focus and aperture settings in the middle, and your swing speed. You can try several sets of parameters until you are satisfied.

good luck