The 'CJ' Tech in Dead by Daylight is when a survivor performs an action as the killer goes to press 'space bar' whilst another survivor is downed near the killer. This forces the killer to pick up the downed survivor involuntarily. Most commonly used to force the killer into picking up someone with decisive strike, or to allow a potential flashlight save.
A common scenario where a The 'CJ' Tech would be applied is when a survivor is dowed near a pallet. 'Crawl to the pallet, imma CJ this fool' - Squoosee. Stunning the killer then vaulting into them as they go to break the pallet will force a pick up animation allowing for potential flashlight saves.