Clark wouldn't even dream that Bruce would remember Valentine's Day other than a day when romantic-themed crime might be more likely. His birthday, on the other hand--

Well, Clark's going to do something there. But he's not going to specifically point out that it's for his birthday, or say happy birthday, or do anything to indicate that whatever his plans are have anything to do with said birthday. Because he believes Bruce's birth is something that should be celebrated, but he knows how Bruce will take it.

"One s'more for you. One for me. S'mores."

It comes with a light squeeze.