§ 2. On Onanism

801. Notion. Onanism (or the sin of Onan) is copulation so performed that from the semen poured out generation cannot follow. This crime perpetrated among unmarried persons is a double sin, namely fornication begun and effective, and pollution in effect. Concerning onanism between spouses it will be said in the treatise on Matrimony (2114 ff.).

The special malice of onanism, when it is committed by unmarried persons, is not rarely unknown; because they easily persuade themselves that less evil intervenes there, where scandal is avoided and the honor of the girl is consulted. Therefore let the confessor not press questions if the penitent seems to be in good faith, nor a special reason is present for admonishing him or asking whether the sin was consummated, for example on account of suspicion of attempted abortion.

Note. To onanism is referred, insofar as inducing its danger, inordinate congress, in which, namely, the natural order of lying together is not preserved: for example when the man lies beneath, or approaches backward in the manner of beasts, or from the side, or standing, or sitting, or in another unusual mode. Whether and what kind of sin it is, see n. 2100.