I have been using the Ham-Sah technique for quite sometime and have read that other have gotten aroused down below during the technique. I for one have only had that happened a few times and that is because something sexual has passed through my mind and within an instant I start to have an erection. I then use the pranayama to suck the energy up and then, wallah all gone.
My question is: Even without any sexually arousing thoughts would you start getting any feelings down below or start getting erections?
Also, I never feel anything coming up my spine or anything but I have for the longest time felt a lot of tingling on my skull. I never tried to pay much attention to it but it happens from time to time during my pranayamas and nowhere else. So I am assuming it does have to do with the Pranayama and I am pleased when it does come because it actually is a little pleasant.

Thanks.