Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 3
As for the discharges, that is less dangerous; most who live unmarried have them from time to time. Only, if they occur too 
often, they are depressing to the vital force. Certainly, they must be stopped; but do not have exaggerated ideas on the matter. To stop them, the first necessity is to discourage sexual imaginations in the waking state. Even if that is totally done, the discharge may still continue at night, because the subconscient keeps the memory and the habit. To stop it, you have to have a strong will before sleeping that it should not happen; also, if you can learn how to do it, direct a strong force on the sexual centre before going to sleep to inhibit this kind of accident. After a time this method usually succeeds.