You would lock the door and start replacing the bottle

You lock the door and you take her flask. Before emptying the flask you take a mouthful and dump the rest. The effect was instantaneous. It became rock hard you were horny as well. You start shagging off thinking how Marge would be in your care. It wasn't long until you shoot a lot into the flask and even sprayed some over her bags.

You wipe them off hastily and you seal the flask shut. When the work was done, you unlock the door only to face Aunt Marge straight on. She peeked on her small bag and notices your bulge hasn't gone off. You try to squeeze away, but she blocked you and pulled out her napkin which she then covered your face. In the attack, your wand dropped. You try searching for it as your vision becomes blurry...

Then it all fades to black...