I don’t know if I overlooked or I am just dumb. The guides I read either did not mention it or just say do it ‘when necessary’ but without describing when is necessary: to stuff something under your lower back aka just above you butt when you use aneros while lying on your back.
Last time I using aneros, I just accidentally shove a chair cushion of one and a half inch thick under my lower back and boom: my first pure aneros induced orgasm(though quite similar to a normal ejaculate-o).
After some rough analyse, I think that the ‘necessary’ comes when the butt of some of us could be so flatten when we lie down that , the tail or the K-tab of aneros would be rubbed against our bed sheet (or on whatever we lied on). The rubbing point would act as a hinge such that when the aneros is ‘drawn in’, the lever will make the head swing away from the prostate, whereas the hinge should be at the perineum to swing the head to knock the prostate.
TL/DR: Shove something of 1-2 inch thick under your lower back when using aneros on your back could prevent a condition that aneros do not function properly.
Source: https://www.reddit.com/r/aneros/comments/c5ru85/a_trivial_tip_on_using_aneros_while_lying_on_your/
I typically remove the curly part of the k-tab on my aneros toys. This keeps it from pressing against the mattress when lying on my back.