Bucky and Sam were standing on the staircase while the reception was taking place in front of their eyes.
They were in their little world, being a few feet away from everyone else in the aisles of the already crowded living room with the rest of the guests that came. They are currently watching their teacher, Fury, getting married to the love of his life and exchanging the vows between the two lovebirds.
Bucky would then reach out to grab ahold of Sam's hand resting on the rail with a smile, but Sam would pull it away because that's a Sam thing to do.
So Sam puts his hand back on the rail seconds after, and Bucky tries for the second time, only for it to happen again.
It went on a few more times with matching smiles growing on their faces each time Bucky went ahead to grab Sam's hand, to miss repeatedly, and for Sam to pull away once more.
Eventually, Bucky was done with the game they were playing. Rather than grabbing the hand, as usual, he reaches out to grab Sam by his shoulders, one arm quickly wrapping itself in position and allowing Sam to lean against his shoulders.
They meet each other by their eyes directly staring one into another, and without a second thought, they share a sweet, simple kiss that they didn't need words to describe their love.