slapping

A scarred traitor screamed at him, lunging at him with a bayonet. Harahel sidestepped the attack and backhanded the man across his face, smashing his skull and sending chunks of his teeth spearing into the face of a heavy-set warrior who was fumbling with the activation stud of a shock maul. The man cried out in pain, dropping his weapon and clutching his ragged face. Harahel clamped his hand over the man’s head and squeezed, crushing his skull. ‘Cowards,’ he snarled, throwing the twitching body into the press of traitors as they scrambled away.

Hammer and Bolter 15: Beneath the Flesh pg. 10