The first thing almost anyone playing men's lacrosse for the first time asks is, "When do we get to hit them?" Lacrosse is a contact sport, and hitting is a big part of the game, but the rules are well-defined and take skill and training to manipulate to your advantage.
There are three legal means of contact, as broken down by the NCAA Men's Lacrosse Rulebook: body checking, stick checking and offensive screening. The latter is similar to screening in basketball, where one player can physically block another offensive player's defender but must remain motionless to do so.
Body checking, less common than stick checking but much more dramatic, involves a defender using his body to strike an offensive player for the advantage. There are three main requirements to the rule. First, the attacker must either be in possession of the ball or within five yards of it. Second, the hit can only come from the front or side. Finally, the hit can only land above the waist and below the neck.
Keeping it safe
As the potential for dangerous contact is high in these situations, there are several clarifications to the rule that players must keep in mind. To avoid full-on football-style tackles, both hands must be kept on the stick while making the check. Additionally, any player who has any part of his body other than his feet on the ground may not be checked.
The rules prompt the officials to keep vigilant for offensive players attempting to draw the fouls on purpose:
"If a player who is about to be body checked turns his back, ducks or jumps in such a manner as to make what started to be a legal check appear illegal, no foul is committed by the player applying the body check."
The term "spearing" is often used to describe another type of illegal body check, one in which the head is used to initiate contact to try to "spear" the opponent.
All these sorts of illegal body checks are considered personal fouls, which result in one to three minutes of a man-up opportunity for the offended team, as the player who committed the foul is made to sit out the length of the penalty, and the other team receives the ball.
Checking with the stick is another area in which the rules delineate very careful boundaries between what is legal and what is not.
The notorious "cross check" is definitely illegal. A cross check is a hit delivered by a player — typically a defender — by holding his stick at either end and striking his opponent with the part in between his hands.
No slashing
What a player may do legally with the stick on defense is to strike an opponent's stick when that opponent has possession of the ball or is within five yards of a loose ball or a ball in flight. This is a very common move in lacrosse and is highly effective for defenders to recover possession for their team.
The illegal side of the stick check is called slashing, also a personal foul. Slashing is a general term describing any illegal hitting of an opponent with one's stick. The officiating of this rule can get tricky, though, as contact is judged by intent and not action. Inadvertent contact is not grounds for a penalty.

While stick checking, the hands of the opposing player — which are, of course, covered by gloves — are considered to be part of his stick. For that reason, hitting them is not considered slashing, though repeated malicious striking of a hand can be called as slashing.
Another illegal move related to stick checking is called warding off. This happens when an offensive player deliberately makes contact with a defender's stick to interfere with the check attempted. Warding off is only a technical foul, though, in this case resulting in the awarding of the ball to the defensive team.
So there you have it — the very simplified dos and don'ts of contact in men's lacrosse. One last thing, though: don't forget your helmet and pads.