The Sitting Technique

Would this work lying in an upright position (90 Degrees, but slightly slouched so maybe 110) on a bed? Because I have no access to a recliner and my room is far too small to fit any sort of furniture in. Could you attempt it and then reply with your results.
Thanks for this technique anyway, I’ll try it tonight on my bed but I would still appreciate a response about the effectiveness of performing this technique on a bed.