Rabbi Rom Leibner replied 4 years ago

Before the great flood in the days of Noah, it says “And G-d saw that the land was destroyed, for all flesh was destroying their ways on the ground”. Our sages explain this to mean that one of their many sins was that they spilled their seed.

This seems to imply that it is bad in G-d’s eyes for any man to do this (there were no Jews then).

There are 7 commandments that all non-Jews are bound by. One of them is sexual immorality.

There is a disagreement among the law authorities on this question. Since there are those that say he is חייב מיתה (punishable by death) for this transgression, if he wants to do Hashem’s will, it would be appropriate to refrain.