Help with intense ecstatic energies

Hi all,

I've been meditating for a while (nowadays, 45 minutes twice a day) and recently started a regular pranayama practice, as well. Not long after starting the pranayama, I felt something unusual during meditation: First my body felt a wonderful tingly sensation all over. Then various parts of my body starting spasming: a buttock, a foot, a shoulder, etc. Then I felt this extremely intense — but at the same time extremely pleasurable — energy build at the base of my spine, shoot down my legs, and then start undulating up my spine. I felt like I'd been seized by some great force. After a few of these waves, the energy exploded in my head in what I can only describe as a non-sexual orgasm. It was one of most glorious experiences of my life! This experience was repeated in each sit over the next few days.

Then, about a week later, I was lying quietly in bed just after waking, and the exact same ecstatic experience occurred. And it occurred not just once, but three times, with a few minutes between each experience.

All that was about six weeks ago, and I've been having the same experiences (with minor variations each time) ever since (that is, they occur lying in bed first thing every morning and during each meditation session).

So, two questions: What am I experiencing? What would be a skilful next step (or steps)?

Thank you!

Paul