The right and left sides of an automobile or the engine are determined facing forward from rear of car or as from the point of view of being seated inside the car, facing the front (ie, from the driver's seat). Driver's side = Left side (We drive left hand-drive vehicles)
Thereof, which side do most guys hang?
In a well-fitted pair of pants, no one should be able to see which side you 'hang'. The majority of men dress to the left. It's basic biology – most males have left testicles which hang lower than the right. It's arguable that our anatomy is designed for us to swing to the left but it's not that simple.
What does it mean to dress to the left or right?
Dressing left and dressing right are terms that most men, at least those who wear suits, know. It's a term used by tailors when fitting suit pants. To "dress left" means that one keeps one's male appendage shifted in the general direction of the left trouser leg. Likewise for the right.
Is forward a direction?
There are definite relationships between the relative directions, however. Left and right, forward and backward, and up and down are three pairs of complementary directions, each pair orthogonal to both of the others.