noun
premature ejaculation
Slang term for premature ejaculation, literally 'three rubs and a half', implying ejaculation after very little stimulation.
彼はみこすり半で悩んでいる。
He is troubled by premature ejaculation.
Medical/formal term for premature ejaculation, while みこすり半 is vulgar slang.
From 三 (mi, 'three'), 擦り (kosuri, 'rubbing'), and 半 (han, 'half'), literally 'three rubs and a half', a vulgar slang term for premature ejaculation.