that was my problem recently. i would be going along and vibrations would come and jolt me wide awake and then they were gone. over and over. no idea how to resolve that.

but the other day i did WBTB and felt the strongest vibrations ive ever felt and they stayed with me until i heard some HS and felt waaaay different all over but kept feeling a major zap that shook me out of the trance. i would say make sure you are really tired when u try it and then the vibrations may stay longer for ya.