Wheeling in a scrum occurs when one team applies uneven pressure or angles against the opposition, causing the scrum to rotate or pivot illegally. This maneuver disrupts the integrity of the scrum contest and poses a safety risk to the players involved. Wheeling is typically penalized by the referee, with the non-offending team awarded a free kick or penalty for the infringement. Preventing wheeling requires proper scrum technique, strength, and coordination among forwards to maintain stability and prevent unauthorized rotation.