Jiujitsu

You have become proficient in ground-based submission techniques that allow you to render your foes unconscious. Once per turn, you may execute a submission attempt against an opponent you have pinned (prerequisite: grappler feat). If you do, roll a strength check and add your proficiency bonus. Your opponent does the same. If you win this challenge, the opponent is incapacitated. This effect lasts for 5 minutes or until the opponent recovers 20 hit points, or is relieved of this condition by other means.

An opponent rendered unconscious in this manner can choose to roll a Constitution saving throw (DC 18) to end this condition at the beginning of each of his/her turns.