Orgasm and ejaculation are physiologically two separate processes, although they usually occur simultaneously—this distinction is the basis for a man's ability to have multiple orgasms.
Scientific Basis Sexologists (including researchers of tantric practices) describe techniques aimed at achieving orgasmic sensation without ejaculation — the so-called "dry" orgasm. This requires a high level of control of the pelvic muscles.
Basic Technique As you approach ejaculation, sharply contract your pelvic floor muscles (the same ones you use to hold in urine) while maintaining stimulation—this attempts to induce an orgasmic sensation while blocking ejaculation.
The training process This skill requires weeks or months of practice, often with solo practice, before it can be successfully used with a partner — it rarely works on the first try.
About the dangers Some techniques (especially pressure on the urethra) are risky and are not recommended for independent testing without consulting a doctor — safe methods rely solely on muscle control, not external pressure.