The proper way to look through your telescope is by placing your eye just behind the eyepiece to take advantage of the eyepiece’s eye relief.
Eye relief measures the spacing from the last surface of the eye lens of an eyepiece to the plane behind the eyepiece where all the light rays of the exit pupil are visible. (The eye lens is the lens of the eyepiece closest to your eye when the eyepiece is inserted correctly into the focusing drawtube.) Your eye should be positioned here to experience the full field of view of the eyepiece. You’ll lose field of view if you place your eye farther away and may even move your eye out of the beam of light from the eyepiece. On the other hand, getting too close will prevent you from blinking and also cause a black ring to appear around the field of view.
Eye relief should be at least 15 mm for the best comfort, but it may be more if you wear eyeglasses.
Longer-focal-length eyepieces generally have longer eye relief. Using a Barlow lens with them to increase magnification will allow more comfortable high-power viewing because the Barlow will keep the eye relief constant.
Eyepieces with long eye relief need rubber or plastic eyecups to shield your view from extraneous glare.