i ALWAYS push it shut...my drive takes barely any force before it starts closing automatically...a slight nudge...
drives are intended to be shut w/ a nudge, or the button...a nudge will NOT damage the tray, unless your drive is extremely cheap (in which case, it would probably fail w/ the button anyway) or you nudge it excessively hard (i.e. punch, kick, shoulder check, running long-jump-kick-super-jumping-jack-punch move, etc.).