You might have seen a pyramid assembled from other 3D pyramids. with elastic stitching making an actual head pillow of this form would get rid of clumping while providing customizable area softness.
This geometry would work well with companion robots. The clustered pyramids with elastic stitching
could imitate, area by area the contours and softness of the human body, with greater durability of form. This might work well with robot girlfriends.
Other robot girlfriend technologies:
The combination of moist areas with clean soft dry areas is something to think about with robot girlfriends. There is a branch of technology called microfluidics, one version of which has molded micro silicone channels used to transport millimolar amounts of chemicals together in soft silicone reactors with valves. This could be a good moist area technology. Amazingly, companion robots could excuse themselves to the restroom a time or two each day to wipe themselves clean.
Another technological improvement to robot girlfriends *might* be a silicone velvet where microfiber cloth size, or smaller threads were used to create the velvet. You might have experienced a fuzzy microfiber cloth, they feel amazing. Just do something like that with shorter lengths as a velvet on silicone.