Uh... OOC I think but I can't get the idea outta my head.
He slips the little piece of chocolate into her hand when she's not looking, and she glances down at the shiny gold wrapper with an eyebrow quirked up.
"What's this, Space Boy?"
He shrugs and puts his hands in his pockets and sways back and forth. "Oooh, I dunno. You humans seem to like these things on this day. They're delicious though, I'll give you that."
Donna looks back down at the chocolate then back up at the Doctor and then pockets the sweet with a slight grin.
"I'm not getting you nothing."
"Didn't expect you to." He looks over at her through the corner of his eye and smirks, and she smirks right back.
...Something like that, Jchan?