Scenario: You're putting it down with moves that would make James Deen (yes, Deen—not Dean) jealous, and you blink. Hey, it was a long night at the bar. When you open your eyes, she's pissed. Because you dozed off.
First of all, reassure her that it's not lack of interest in her that inspired your nap. She's not so boring in bed you can't keep your eyes open. You just had a few too many.
And second? Maybe cool it with the liquid courage.