My sister is currently in bed drunk

She's a lightweight but she's never been drunk before. She's pretty. She's about 120 pounds and 5'6. I'm doubting she'll be fine tomorrow. She's currently sleeping next to me. I'm tempted to touch her ass. I've never been this close to her like this before. I'd love to stick in her ass right now but I don't know if I should. What should I do?