The pelvic floor muscles (pubococcygeal, or PC muscles) are directly involved in the physiology of orgasm — strengthening them often increases the intensity of orgasm.
The Basics of Kegel Exercises The muscle you use to stop the flow of urine is this very muscle—contract it for 5 seconds and then gently relax it, 10-15 times, several times a day.
How does this relate to orgasm? During orgasm, these same muscles contract rhythmically (at intervals of about 0.8 seconds) — the stronger the muscle, the more noticeable this rhythmic contraction is.
The "orgasmic plateau" and its prolongation Maintaining stimulation even when the sensation "peaks" (the plateau phase), rather than striving for a quick climax, often leads to a more intense final orgasm.
Practical advice Regularity of Kegel exercises (for several weeks) is necessary for noticeable results - instant changes cannot be expected with a single exercise.