Hello- It's been a while since I've read this fic but here is what I remember.

— Spuffy are in high school
— It's PG/PG13
— Buffy goes to a party and watches Spike. She counts his smiles and knows how many she's seen.
— Buffy gets drunk and needs to stay the night. Spike takes care of her and brings her to his room.
— In the morning, Spike feeds her pancakes

I vaguely remember it being called Smile but I'm coming up empty handed searching for it so I'm not sure if that was the title.

Thanks!

Apparently it just took me posting for me to find it: https://web.archive.org/web/20101127060041/http://nocturnal-light.net/fanfiction/story/499/1/Smile