How to tween brick to mouse position?

Hello, I am making a Harry Potter style game. I am currently making the part, where you can press button (r) and it will turn you invisible, make a part which would it sit you on and then the part created would follow your mouse. I know how to make the character invisible, how to make a part that will sit you it on all of it on keypress r, but I dont know how to make the brick follow the mouse. I know you can just get mouse position, but that doesnt work on air ( i think ), so I dont want to do that. I dont have any code written yet. I will start after I get some answears. Also want to mention it to be tween, because just changing parts position would be kinda not nice. Thanks in advance!