A sibling, most often either a step-sibling or close friend who is considered a sibling, to whom one is sexually attracted. In almost all cases, one has no aversion whatsoever to acting upon this attraction.
Isn't that his sister he's making out with over there? - Nah, they're just sinblings. His mom married her dad.
The art of playing a battle royalegame with your buddies, completely straying away from the group and not informing them of your location. Also includes getting downed and thirsted extremely far from the squad and then audibly crying/pleading for help, then blaming fellow teammates for their incompetency.