Sex with your ex is almost always a terrible idea. You know that. But after a few rounds of Jägerbombs "for old time's sake," boning your ex for the same reason suddenly transforms into a great idea.
She's at the bar with her old friends, and that familiar smug attitude that simultaneously aggravates you and attracts you to her is back. Her face is bright, and you're staring.
Our advice here? What the hell—go for it. But only if you're single and over her. We'd walk you through pulling this off, but you've had sex with this woman before, remember?