She'll flinch at your hands moving from her waist to her lower back, back up to her neck and cheeks because it's been some time since she's been caressed by hands that are wandering to remember old terrain.
Try to decipher the goosebumps on her arms and thighs like Braille with your fingertips. What do you read? "I missed you"? "Don't go again"? "Stay"?
Maybe she won't meet your gaze immediately. It's oddly scary to look someone in the eye when you've seen them go dull from too much heartache. Instead, close your eyes and lean in. She'll close hers too, and you can feel the sadness melt away when your lips are almost close enough to hers.
She'll gasp ever so slightly when you finally kiss her. It'll feel like electricity in your lips and she'll be dizzy from anticipating this moment for so long. Her lips have lingered on coffee mugs and beer bottles, but haven't been warmed by another pair since you left. Reignite them with your own.
Hold her close and kiss what you can. She's timid but so lifted by the fact that you're here in her embrace. If she holds you too tightly, allow her this once. She's trying to make sure this isn't another one of her far fetched dreams that wake her in the morning.
She may be rough and kiss too hard, too fast. It won't always be like this, but she isn't sure if she'll be afforded the opportunity to feel your kiss again. She's feeding a hunger that's been growing since you said good bye.
If she clings to your frame when you say good night, whisper softly into her ear about how you'll be back. Come back, and kiss her again. Kiss her until you forget what day it is and how long it had been since you last kissed her. Kiss her good night but not good bye because there's a difference between the two and trust me, she knows. She knows the difference because you've kissed good bye before, and a good night would simply constitute to finding you once again.