Maru
You're speaking to a Ritual Queen my dear (one of the ones who requested the "Threads on Magick and Rituals" section here on AT).
I love Ritual and have a number of Tools.
But it is me and my belief that makes them all so.
"They" don't work better - I "work better" with them within my belief framework.
Superstition is belief (just like religion - and I'd better put IMO here. Lol).
Cards could be placed by the side of the pillow rather than directly under it avoiding uncomfortable lumps.
I can imagine under the bed could work too.
I do put things under or beside my pillow - now-and-again.
Well belief and intent is a very integral part of manifestation work.
I have a friend who is struggling right now in the belief department. I tell him if he doesn't actually believe his life will get better while doing all the therapy/healing work necessary to get there, then things will not likely improve on their own. Same with dropping addictions or bad habits.
I am very ritualistic as well, just not about where I place my cards. LOL. If the cards want to be moved, then they can actually tell me... I do work on that level with my tools.
Actually, I use my cards on top of my graphics tablet for work/personal illustration so maybe that helps with keeping them full of my own energy... though I have a list of strange rituals that I do without any real prompt.