pyautogui.dragTo(100, 200, button='left') # drag mouse to X of 100, Y of 200 while holding down left mouse button
pyautogui.dragTo(300, 400, 2, button='left') # drag mouse to X of 300, Y of 400 over 2 seconds while holding down left mouse button
pyautogui.drag(30, 0, 2, button='right') # drag the mouse left 30 pixels over 2 seconds while holding down the right mouse button