Anticipation
Knowing Ray the way he did Fraser had been expecting the snowball. Not at that very moment or to the back of the head but in a general sense. There was just too much pristine snow for Ray to be able to resist for long. Fraser was just glad it hadn't been to his face or worse, a handful shoved down his pants. That would have been awkward, and cold.
Quirking a smile he turned and announced in his best mountie voice "That was an act of war, Ray."
Ray, being Ray, had responded with another snowball and an almost maniacal laugh. Followed immediately by the words "Bring it."
The battle was short lived, but by the end both were laughing and covered in snow. What Fraser hadn't expected though he'd hoped and longed for was when they were both back in Fraser's flat warming up over hot chocolate and soup was for Ray to concede his loss and seal his surrender with a kiss.