Huernia pillansii is a clump-forming stem succulent. The dwarf plant reaches heights of only about 15 cm.
Its soft, hairless stems are erect or ascending. Stems become up to 1 cm in diameter, their shape initially globose, later ovoid or cylindrical. Conical tubercles tipped with soft bristles cover the stems in vertical or oblique, spiralling rows, causing the stems to be furry to the touch.
The species is endemic to the Western Cape and the Eastern Cape, only in the Little Karoo and the southwest of the Great Karoo from Montagu to Steytlerville.
The habitat is Nama Karoo and succulent Karoo where the plants grow in arid and semi-arid conditions under other vegetation on stony flats and slopes. The species is not considered to be threatened in its habitat early in the twenty first century (White and Sloane, 1937; Vlok and Schutte-Vlok, 2010; http://redlist.sanbi.org).