Most commonly two men and two women, but four men can also enjoy this position.
The bottoms (be them men or women) set up in doggystyle positions on all fours parallel to each other.
The tops then mount the bottoms. Thus you have the two couples facing the same direction, side by side.
The tops then lean in and kiss.
Thus re-enacting a roman chariot race.
"Yeah man, but I gotta say, you're a pretty bad kisser."