Feeling lightheaded = p-wave?

Trying to keep it short & simple:

In my previous Aneros sessions the sensations I've mostly felt have been pleasurable pulsating and buzz in the anal / pelvic region, until two days ago. Having spent several hours with the Progasm, I started wondering what would happen if I concentrated on the thought of ejaculating - shortly after focusing, I experienced what felt like a case of vertigo, losing momentarily my sense of balance and feeling as if my legs were rising off the ground (luckily I was in my usual position, leaning on the bed with my knees on the floor). Quite a psychedelic bout, and like the major sensations in my earlier sessions, seemed to come out of nowhere.

The odd thing was that I didn't feel much in the pelvic region, aside from some considerable involuntary contractions moving the Progasm during the event. I haven't really understood what constitutes a p-wave, just wondering whether this sensation might've been one.