As tempting as it is to rekindle the relationship by reminding her how good she had it (physically) with you, and regardless of how much you miss her/miss seeing her naked, sex with your ex is always a bad idea.
Post-breakup sex confuses the situation. Connecting during sex doesn't change or fix the issues at hand. It only clouds your judgement, and it will inevitably flood you with incoherent, unreliable messages about your feelings and the relationship.
Plus, we know you hate to admit it, but it will hurt that much more when she packs up to leave after, when you wake up alone. Don't get in the business of putting bandages on gaping wounds. It doesn't help the healing process, and it will only hurt that much more when you finally rip the damn thing off.