In first-person shooter games, leaning is a game mechanic that allows characters near corners or other cover to lean around the cover. This reduces or eliminates exposure of the shooter's feet, legs, and torso, which the target may use to counterattack.
Battlefield 4 includes a contextual leaning system. The system is activated by standing near appropriate cover, which is signified when the character's weapon is tilted and moved slightly back. The soldier then actually leans when the Aim button is pressed.
The leaning system also distinguishes between vertical cover (e.g. building corners) and horizontal cover (e.g. window sills), allowing the soldier to lean to the side or peek above as appropriate.
On the PlayStation 4 and Xbox One versions of the game, the player can use the motion sensor on the DualShock 4 controller and the Kinect camera, respectively, to lean without using the contextual leaning system.