Just as an FYI, orgasm thru masturbation can relieve muscle tension and cramps for some women. Something I learned from my first Sensei.

Here's a great Tantric technique, called Yoni massage, but it works best if performed by your partner.

Lingam massage, for men, is also a lot of fun. I especially like having it performed when I'm bound by my slave. It becomes a contest to see if she can make me cum before I decide I'm ready. Lol, makes her feel all Mistressy.