get mouse position during drag

[xxvii]

Hello,
I'm trying to get the mouse position while dragging the swiper, to implement a "follow cursor effect", exactly like this: https://codepen.io/Nysh/pen/jOMogZa

However, Swiper doesn't have a drag event as far as I know, and I can't get the mouse position with:
window.addEventListener('drag', foo());
window.addEventListener('dragover', foo());
document.addEventListener('drag', foo());
document.addEventListener('dragover', foo());

Any suggestion?

Thank you