godan verb (-ru)
Slang verb derived from オナニー (masturbation). Casual and somewhat crude; used mainly among close friends or in informal contexts.
See also: オナニー
昨日、彼は部屋でオナってた。
Yesterday, he was masturbating in his room.
オナる前にちゃんと手を洗えよ。
Wash your hands properly before you masturbate.