CosmicIron says to not mix anything with SSILD as you lay back down after a WBTB, and that may be the best until you really get SSILD working for you, but I do sometimes mix in MILD and/or mantras when the HHs start appearing. This was much later though, well after successfully using SSILD and then my variation of SSILD for quite a while. It seems that MILD and mantras are more powerful when your mind is getting into those early stages of sleep (that are often accompanied by HHs).
-That seems like a good choice for you. I made a similar decision early on. If anything is draining and frustrating, it is better to take a break from that particular training and focus on things that fit you better.
-SA: check out Sageous' recent post and see if it helps you. I think it is very worthwhile:
http://www.dreamviews.com/attaining-...ml#post2193957
Bookmarks