It was a feeling she was very familiar with; she'd felt it for over a thousand years. It was the magical connection to the celestial body that was the physical symbol of her office. It was reminding her that she needed to oversee the raising of the morning sun.
Normally the Princess of the Sun would at this point rise from her bed and start her day, but for several reasons she was slow to do that this morning.
1. It was Sunday and that was Celestia's day off.
2. As the alicorn slowly opened her eyes she could see that the floor in this dimly lit room had a layer of drained beer, bourbon, rum, and champagne bottles with empty pizza boxes scattered amongst now consumed packages of cookies, cakes, and pretzels. It was this collection of refuse that was contributing to her fuzzy head, cotton mouth, and her somewhat upset stomach.
3. Another factor contributing to her upset stomach was the sleeping mare sprawled across her chest. Celestia looks down at Heartbreaker and in spite of her sore belly she couldn't help but smile. It had been far too long since she'd had an evening like last night, and the slight hangover and upset tummy was a fair price for the fun her and the mare had enjoyed.