Hard mode is a slang term referring to a particular practice of male sexual abstinence, specifically the avoidance of porn, masturbation, and orgasm.

It's important to note that hard mode does not mean "no sex", but rather, specifically "no orgasm."

Semen retention qualifies as variation of "hard mode," however it separates the concepts of male orgasm and male ejaculation. In semen retention, you can learn, with practice, to achieve sexual orgasm without ejaculating.

‍